Panarctic Flora


1 Introduction

2 Delimitation and subdivision of the Arctic for Panarctic Flora

3 Arctic vascular plants

4 Casual taxa

5 Excluded taxa

6 Taxonomic treatment

7 References

8 Distribution table

1  Introduction

1.1  Aims

A Panarctic Flora Checklist could be compiled in several ways. The simplest way would be just to assemble the names in use in the different parts of the Arctic and the distributions reported regionally for the named taxa. Recent lists exist for nearly all regions: for Russia by Sekretareva (1999, 2004), for mainland Norway, Svalbard, and Jan Mayen by Elven et al. (2005), for Svalbard by Elven and Elvebakk (1996) and, for Iceland by Kristinsson (1987, 2010,, for Greenland by Böcher et al. (1978) supplemented by Feilberg (1984a), Bay (1992), and Fredskild (1996), and for North America perhaps by Shetler and Skog (1978) or by the volumes that have appeared of Flora of North America.

Such a compiled list would have some major disadvantages. The same name has often been applied in different meanings in different areas, e.g., the names Cerastium alpinum and Papaver radicatum have been applied differently in Europe, Greenland, and North America, the names Festuca hyperborea and F. brachyphylla have recently been applied differently in Russia from elsewhere, the name Dryopteris carthusiana is applied differently in the Nordic area and in Russia, and several names in Potentilla and Dryas have been applied differently more or less everywhere. It would be impossible to make a meaningful distribution table based on these lists. And – even more important – it would be impossible to use the Checklist for, e.g., biodiversity estimates and conservation purposes as the criteria for rare and vulnerable plants would differ appreciably among regions. Such a list would not have any value above that of the primary sources which are easily accessible. To produce such a list is not a very challenging task. We have therefore produced something very different.

The Annotated Panarctic Flora (PAF) Checklist is a compilation of accepted names and synonyms, and an evaluation of all vascular plant taxa at ranks of family, genus, species, subspecies, varieties, and hybrids (but only those with an independent existence), occurring regularly within the Arctic as circumscribed for the Checklist. We also comment on taxa reported but not accepted for the Arctic ("Excluded taxa") and on a majority of those plants found in the Arctic only as accidental weeds and escapes ("Casual taxa"). More specifically, we aim:

  1. To present an authoritative survey of arctic vascular plants applying the same criteria for circumscription, ranking, and naming of taxa across different plant groups, across differences in reproductive modes (sexual, asexual), and across geographical regions where different botanical traditions have prevailed.

  2. To give a rough survey of the distribution and frequency of all taxa in biogeographical regions and bioclimatic zones (see Yurtsev 1994 and Elvebakk et al. 1999).

  3. To present a single list of scientific names for non-specialists, identifying and standardizing the names for plants that have gone under different names in different regions.

  4. To achieve consensus of taxonomic views on arctic plants among scientists from different nations and scientific environments.

  5. To initiate a full Panarctic Flora treatment. This treatment will, in time, include keys and descriptions, information on reproduction, habitats, and more detailed distribution data.

It has been unexpectedly difficult to reach a consensus Checklist, for reasons both biological and cultural (due to regional differences in scientific approaches). The problems of different botanical traditions are due to largely independent developments of the biological sciences in the so-called 'western' and the 'Soviet' sectors in the 20th century. The political divisions made scientific contact and exchange of ideas relatively difficult. The criteria for what should be considered a species or a subspecies became rather different in the two schools of thought. Now, many years since the political reasons for this differences have disappeared, the divisions are still evident in taxonomic botany.

1.2  Procedures

Russian collaborators have supplied initial proposals for taxa to be included, proposals for their taxonomic status and names (the 'PAF proposals' often referred to in the specific treatments below), and draft distribution tables. These contributors were resposible for sections of the Arctic Flora of the USSR that was completed in 1989. At the end of 1999, numerous drafts were still missing and these have subsequently been produced by Elven. The authors of initial drafts are listed among the contributors to the Checklist above.

Editing and supplementing the drafts has been the main task of Elven, supported by botanists in Fairbanks, Ottawa, Montreal, and St. Petersburg. Razzhivin has been responsible for databasing information and for communication between the Russian botanists and the Norwegian editorial office. To the initial drafts has been added information on nomenclature and synonyms, places of publication, types, chromosome numbers, supplementary data on distribution, and discussions ("notes"). Elven has made changes to the initial proposals in taxonomic treatment and names and has added notes, partly due to comments received from the more than 125 external contributors, but mostly due to his own idiosyncracies. The initial proposals have in general been so extensively changed that they now more often than not reflect views different from those of their authors. This has been considered a necessary part of the process of reaching a 'Panarctic' view.

Edited drafts have been distributed for critique back to the original authors of proposals, to the Editorial Board, and in many cases to external reviewers, mostly in North America (due to the initial proposals mainly being made in Russia). The drafts have been discussed with the Russian and North American authors in several meetings in St. Petersburg, Oslo, Ottawa, and Fairbanks during the period 1999–2009. To all these peoples the editors are most grateful. Nearly every comment has been taken into account in the final editing, but the treatments have been adjusted according to the guidelines decided for the Checklist (see Elven 1999). The taxonomy and nomenclature presented in the Checklist is not final in any way, for it is evident we still have a very spotty knowledge of many plants throughout the huge Arctic zone. Still prevalent are differences in opinions among the scientists in the countries with arctic parts. The notes include many of these views and may therefore be more informative than the actual taxonomic and nomenclatural solutions chosen.

An Editorial Board (Elven, Murray, Yurtsev) has been responsible for final decisions as to which taxa to include, their taxonomic ranks, and names. The Editorial Board has worked towards consensus or – in cases where the opinions differed strongly – made compromise proposals. In some cases without agreement, majority decisions with minority comments have been prepared (see especially the genus Dryas). The full Editorial Board could not meet for final decisions before the conclusion of the Checklist, due to the untimely death of our dear friend Boris Yurtsev in 2004. The final account has therefore been produced by the remaining editors: Elven and Murray. This account, as now presented, is not in full accordance with the views of most of the original contributors, or of the commentators, and in some instances not in accordance with the views of the editors either. Such is life. It is, however, the best we are able to do with the present state of knowledge of arctic plants.

In summary, the original, idealistic aim of a consensus Checklist has not been fully reached. During discussions we have, however, reached a deeper understanding of the reasons behind the different viewpoints, and in many cases also solutions different from and hopefully better than the original proposals. In these cases we think the Checklist is a step forward compared with previous accounts. In many other cases we have rather reached compromises that accommodate the differing views, and those views are reflected in the notes. In any case, we now have a much deeper understanding of how the scientists think in the different 'camps'.

2 Delimitation and subdivision of the Arctic for the Panarctic Flora

2.1 Delimitation

The Arctic has been circumscribed in numerous ways for different purposes, characterized by certain climate(s) or by more or less continuous permafrost, geographically as, e.g., north of the Arctic Circle with some period with 24h day and night, biologically by a special composition in vegetation and/or species, or even politically.

For the Panarctic Flora, we combine climatic and biological criteria in a bioclimatic circumscription, discussed in more detail by Elvebakk et al. (1999; see also other papers in Nordal and Razzhivin 1999). We define the Arctic as a region where even the lowlands are non-forested because of the restrictions enforced by a short vegetation period (mostly less than 60–90 days) with low summer temperatures (nearly always <10C for the two warmest months) and/or a low heat sum, and a long winter with stable or nearly stable frost and snow. In regions with continental climates, this corresponds to areas north of the polar treeline. We accept, however, that pockets of trees may occur in especially favourable sites in the Arctic. We exclude areas where these climatic conditions are fulfilled in the mountains only (e.g., almost all of northern Scandinavia). It becomes more problematic to apply the treeline criterion in more oceanic regions. The coasts and islands around the North Pacific are non-forested south to northern Kamtchatka, the Commander Islands, the Aleutian Islands, and the major parts of the Alaska Peninsula. The same is the case around the North Atlantic where forests are absent from almost all of Iceland, the Faeroes, parts of the northern British Isles, much of the coast of northern Norway, and the east coast of Labrador and south to some parts of Newfoundland. In these areas, however, the summer temperatures are higher and the winter temperatures much higher (in many areas with infrequent and unstable snow cover). At the same time, sizeable pockets of forest (or at least very tall shrubs) are found in interior fjord in southern Greenland. In these areas we have applied the two temperature criteria: (1) middle temperatures for the warmest month (usually July) of less than ca. 10C; and (2) a distinct winter frost climate. By these criteria the following regions are excluded from our concept of the Arctic: in the North Pacific the Commander, Aleutian, and Pribilof islands, and most parts of the Koryak Coast and of Alaska Peninsula and surroundings; in the North Atlantic all of Newfoundland, most parts of the Labrador coast, almost all of Iceland (and of course the Faeroes and Britain), and almost all of mainland Norway.

We have excluded from the Arctic those mountain areas where half or more of the bordering lowlands do not fulfill the criteria. Where the mountains run in a N–S direction, this means that our arctic boundary is drawn straight across the mountains, e.g., in the northern Urals between Europe and Asia, in the Verkhoyansk Mountains in eastern Siberia, and in the Richardson Mountains in northwestern Canada. This criterion is more problematic where the mountains run in a W–E direction, as they do in the Kolyma Mountains in northeastern Asia, the Brooks Range in northern Alaska, and in the British Mountains in the Yukon Territory. These are commented on below. From a phytogeographical point of view, the exclusion of the near-arctic mountains is problematic as these often are richer in 'arctic' species than are the more northernly situated and non-forested lowlands, e.g., in northern Scandinavia, the Khibiny Mountains in the Murman area, in Iceland, and in northwestern Canada.

Our delimitation of the Arctic deviates in one or more aspects from the majority of those previously applied for botanical purposes. Compared with Löve and Löve (1975a: xi), we are more restrictive in the oceanic parts of Iceland, Labrador, the Russian Far East, and partly in continental Siberia, whereas we include the Hudson Bay shores. Compared with Flora Arctica URSS (Tolmachev and Yurtsev 1960–1987), we exclude many of the areas there considered as arctic in the Russian Far East (e.g. the Anadyr River basin, the Penzhina River basin, and the southern parts of the Koryak coast) and also some parts in the west on Kanin Peninsula and the Murman coast. Compared with the authoritative survey of Yurtsev (1994), we follow his delimitation except for the North Atlantic regions where we accept as parts of the Arctic much of the Murman coast, small parts of mainland Norway and Iceland, and all of Greenland. This deviation is due to a difference in principles. Yurtsev argued that the North Atlantic areas should be excluded because of the presence there of a number of typically non-arctic species (e.g., Calluna vulgaris and Nardus stricta). Elvebakk and Elven argued that this would be contrary to an application of bioclimatical criteria and would result in an imbalance between Atlantic and Pacific regions. They contested the application of floristic criteria as based on a circular argument ("these areas are not arctic because they contain non-arctic species" and "these species are not arctic because they do not occur within our meaning of the Arctic") and stated that if these criteria were applied, we should also exclude from the Arctic larger parts of the North Pacific coastline at least north to the Bering Strait. Compared with Sekretareva (1999, 2004) for the Russian areas, there is an almost exact correspondence between our delimitation and her 'true' Arctic.

The delimitation as applied by PAF is shown in Fig. ** Internal note: Figure and figure number to be included and includes as arctic parts of the following countries and (in Russia) major geographic regions, with abbreviations used throughout the main text: Iceland (ICE), Norway (NOR), European Russia (RUS), Siberia (SIB), Russian Far East (RFE), U.S.A. (Alaska, ALA), Canada (CAN), and Greenland / Kalaallit Nunaat (GRL).

In the distribution tables, the Arctic is further subdivided in two ways: floristic regions, depending mainly on chorology and assumed past history, and vegetation zones, depending mainly on bioclimate. Both are mapped by Elvebakk et al. (1999) and the floristic regions by Yurtsev (1994), but some changes have later been made to both classifications.

2.2 Floristic regions

The floristic regions are circumscribed so as to have common features independent of the general thermic south – north variation (i.e., the zonation). These features we assume to have mainly historical causes. Some of the regions cross the national borders. Many of the delimitations have been much debated and are still controversial among the PAF collaborators, see comments below. The regions applied for the Checklist are shown on maps in Figs. **-**: Internal note: Figures and figure numbers to be included.

Northern Iceland – Jan Mayen (Ic)

We consider as arctic the northernmost peninsulas of Iceland from Hornstrandir in the west to Langanes in the east, and also the northern offshore islands. This includes parts of the provinces INv and INo as applied by Flora Nordica (Jonsell 2000 onwards). The delimitation was proposed by Kristinsson, corresponds with the summer temperature criterion, and is unproblematic from our criteria. However, it excludes the inland mountains which have a larger arctic component in their flora than have the northern coastlands.

Yurtsev (1994, in comments) proposed the Norwegian island of Jan Mayen as a separate region. Jan Mayen is a young, actively volcanic island (500,000 years old, at most). We merge it with northern Iceland for practical reasons. Jan Mayen is very poor in species (Lid 1964, with some subsequent additions) and negatively defined as ca. 95 % of its vascular plants are in common with all three neighboring areas: eastern Greenland, Scandinavia, and Iceland. The main reasons for inclusion of Jan Mayen in 'Ic' are that it is part of the same geological (volcanic) mid-Atlantic structure, that it does not deserve rank as a separate region, and that the differences from eastern Greenland (ca. 500 km apart) are more pronounced than those from Iceland (ca. 550 km apart) and from Norway (more than 800 km apart).

Iceland and Jan Mayen have both been extensively glaciated during the Pleistocene. Askell Löve assumed survival of numerous species in northern and northwestern Iceland in refugia during at least the last glaciation, especially in the geologically relatively old northwestern West Fjords. The distribution data supporting this hypothesis were largely produced by Löve himself. Several of his records have not been supported by subsequent investigations, and tens of his most sensational reports may be fictious (specimens 'planted' in the herbaria). We cannot exclude refugia in Iceland during the last (or earlier) glaciation (e.g., Rundgren and Ingólfsson 1999), but independent supporting evidence is absent. We therefore at present assume that the entire Icelandic flora is postglacial.

The Iceland part is an oceanic region with some local features, floristically different from both southeastern Greenland and Scandinavia. The Atlantic European element is stronger than in any other region, probably due to the comparatively mild winters. Some occurrences may be related to the extensive bird migration between western Europe and eastern Greenland, with resting sites in Iceland. An especially favourable combination in some sites are wetlands (with birds) and hot springs (with geothermal effects). Several species reach their northernmost sites in the world in hot spring areas in Iceland (and eastern Greenland).

Even if Iceland is situated on the mid-Atlantic ridge and much closer to Greenland (ca. 300 km) than to other parts of Europe (ca. 800 km), the major parts of the flora of Iceland are European. However, the short history since the last glaciation and the frequent disturbance by volcanic activity gives a distinct character to the Icelandic flora. There are no "good" endemics at species level (but some in genera like Euphrasia, Hieracium, Pilosella, and Taraxacum), but often the Icelandic plants are subtly different morphologically from their counterparts in northwestern Europe (and Greenland – North America), perhaps recognizable at ranks of subspecies or variety (e.g., in Armeria maritima, Juncus arcticus/balticus, Luzula multiflora, and Silene uniflora). No parts of Iceland were accepted as arctic by Yurtsev (1994), but the climatic and vegetation conditions in the northernmost parts closely correspond to those found in parts of Beringia accepted by Yurtsev as arctic.

Northern Fennoscandia (FN)

This region includes parts of (mainland) Norway and of Russia. In Norway we include as arctic the northernmost peninsulas and islands of the province of Finnmark eastwards from the island of Magerøya (North Cape), in the easternmost parts south to the Vadsø – Ekkerøya area on the Varanger Peninsula. In Russia we include as arctic parts of the Murman area in the northern half of the Rybachi Peninsula, Kildin Island, and the mainland Murman coast of the Kola Peninsula from Teriberka in the west to north of the Ponoj River basin in the east. The delimitation corresponds well with the summer temperature criterion but not equally well with the forest line criterion as there are large non-forested coastal regions west and southeast of the Norwegian arctic 'strip'. However, these have higher summer temperatures, in the west also quite mild winters with intermittent snow cover. The delimitation landwards is problematic in both Norway and Russia because the arctic coast borders on low but bald mountains dissected by more or less forested valleys and fjords. The arctic 'strip' in Norway is slightly broader than the one proposed by Moen (1999). It excludes, however, all of the more interior Scandinavian mountain range (in Norway, Sweden, and Finland) and the Khibiny Mountains (in the central Murman area) which have a much higher concentration of otherwise arctic plants than what is found on the coastal arctic 'strip'. The vegetation pattern in the areas assigned as arctic corresponds to what is found in parts of Siberia and North America assigned as arctic, even if the floristic composition has a small Atlantic European component.

The entire region has been glaciated during the Pleistocene, also during the last glaciation. There has been an extensive discussion about possible refugia (nunataks and/or coastal forelands), for the arctic parts in earlier times especially by Nordhagen (1963) postulating coastal foreland refugia on the shelf. The current views are divided, and coastal refugia at least during the last part of the glaciation have been proved by palynological and macro-fossil evidence in the northern parts of Nordland province (Vorren 1978; Vorren and Alm 1999; Vorren et al. 1988). At present, we have no strong evidence for refugia inside the arctic parts, but these parts became ice-free much earlier than most other parts of Scandinavia and may have been recruited by plants from coastal refugia to the east and to the west.

A few endemics are present, partly at fairly high taxonomic levels (Puccinellia finmarchica), and some highly disjunct taxa with an Asian connection. Otherwise, the connections are distinctly European. Some Atlantic European species reach the western parts, whereas the main components are boreal to arctic European and Russian. The parts we accept as arctic have a gradient in climate from oceanic in the west to continental in the east, connected with colder seas with winter ice cover in the east.

The region is poor in Siberian floristic elements present in the next region (these are actually better represented inland in northern Fennoscandia, away from the arctic coast). The entire region has had some influx of taxa from the Scandinavian mountain range. This region was excluded from the arctic by Yurtsev (1994) but is arctic according to the climatic criteria.

Kanin – Pechora (KP)

This lowland region includes the major parts of arctic northeastern European Russia: the northern half of the Kanin Peninsula, Kolguev Island, and the Malozemelskaya and Bolshezemelskaya tundras ('Terra Samojedorum') including the lower Pechora River drainage and the Vorkuta area (in the Borderline Arctic).

The entire region is assumed to have been glaciated during the Pleistocene, including the last glaciation.

The region is continental, with a more pronounced Siberian floristic element than found in Fennoscandia, but still with strong European elements. It includes only a few endemics at rank of species. The flora is well known and mapped by Tolmachev (1974–1977). There are some problematic occurrences of boreal plants in the Borderline Arctic in the Pechora drainage.

Svalbard – Franz Joseph Land (SF)

The region includes the high-arctic Norwegian islands of Svalbard (Spitsbergen and surrounding islands, Bear Island) and the Russian islands of Franz Joseph Land.

The region has been heavily or entirely glaciated during the Pleistocene and is still extensively glaciated. There is, however, increasing geological evidence that there may have been ice-free refugia (of a high-arctic character) in its westernmost parts, at least during the latest and coldest phase of the last glaciation. Whether these refugia could harbour vascular plants, or were too harsh, is not known.

The flora of Bear Island (Engelskjøn and Schweitzer 1970; Elven and Elvebakk 1996) combines features of northern Scandinavia and Svalbard proper but is depauperate due to the isolated position and small size of this island and to a nasty, foggy, unfavourable summer climate.

The fairly large archipelago of Svalbard (62,700 km²) is floristically much richer (but still poor compared with other regions) and combines elements in common with arctic Russia and Greenland, with comparatively few connections to mainland Scandinavia. Several predominantly North American and Greenlandic species have their only Eurasian occurrences in Svalbard or there and in East Chukotka / Wrangel Island. The number of endemics at species rank is very low (perhaps only three), and those found are probably of fairly recent origin.

The archipelago of Franz Joseph Land is still very extensively glaciated and is negatively defined floristically. All its known taxa are in common with Svalbard.

Polar Ural – Novaya Zemlya (UN)

This European Russian region includes Polar Ural (the northernmost extension of the ancient Ural mountain range) northwards from a line between the Ussa River and the lower Ob River, the Yugorskiy Peninsula, the island of Vaigach, and the two islands of Novaya Zemlya. We deviate from some other classifications by including Novaya Zemlya and Vaigach in the European parts. Jalas et al. (1972 onwards) included the mainland regions and Vaigach in the Flora Europaea area but excluded Novaya Zemlya (and Franz Joseph Land).

Most or all parts of this region have been glaciated during the Pleistocene (and large parts of Novaya Zemlya still are) but with comparatively short distances to the non-glaciated parts of the Urals.

The region is transitional floristically between arctic Europe and Asia but with a separate mountain range element connected to the Urals. Some Urals endemics reach or are confined to the arctic parts, whereas most or all proposed endemics in Novaya Zemlya and Vaigach are dubious or assumed recently evolved.

Yamal – Gydan (YG)

This Siberian lowland region includes the two northwestern Siberian peninsulas of Yamal and Gydan, the surroundings of lowermost reaches of the Ob River, and the hilly plains between the Polar Ural and the Jenisei River estuary.

Most or all parts of this region seem to have been glaciated one or more times during the Pleistocene (also during the last glaciation) but it is close to the eastern limit of the northern European ice shield during the last glaciation.

This region has a stronger European and western Siberian floristic element than the other parts of northern Siberia and also a specific western Siberian element, often found downstream along the Ob and absent from areas farther east and west. Many Russian botanists consider that the main west–east floristic boundary in northern Europe and Siberia runs between this region and the next (Taimyr – Severnaya Zemlya).

A problematic feature for us is the lowermost reaches of the Ob where numerous more southern species reach or border on the Arctic. The boundary along the lower Ob should perhaps have been drawn farther north than proposed by Yurtsev.

Also the eastern boundary is problematic. The boundaries between several Siberian regions have been drawn along the major rivers. The Jenisei River separates between the regions Yamal – Gydan (YG) and Taimyr – Severnaya Zemlya (Tm), the Khatanga River between Taimyr – Severnaya Zemlya and Anabar – Olenyok (AO), the Lena River between Anabar – Onelyok and Kharaulakh (Kh), and the Kolyma River between Yana – Kolyma (YK) and West Chukotka (CW). This means that homogeneous floristic elements that follow the rivers and river valleys in most cases are split on two regions. It is often difficult to decide from the collections, and from the published distribution maps, on which side of the river they have been collected.

Taimyr – Severnaya Zemlya (Tm)

This Siberian region includes the Severnaya Zemlya and Kirov island groups and the Taimyr Peninsula between the Jenisei and Khatanga rivers and north of the (boreal) Putorana Plateau. The boundary runs north of the towns of Norilsk and Khatanga but across the settlement of Dudinka (which thereby becomes an important borderline arctic site).

This region is situated at the eastern end of the North European and northwestern Siberian ice shield during at least the last glaciation. Important parts of the area have probably not been ice-covered during the last glaciation and perhaps not by any of the Pleistocene glaciations, especially in eastern Taimyr and in the Byrranga Mountains on the Taimyr Peninsula.

The mainland area is a floristically rich region with several endemics in the river valleys and in the Byrranga Mountains, and with floristic connections southwards over the Putorana Plateau and the Central Siberian highlands to the Central Asian mountains. A distinct element of endemics present in the Putorana and Taimyr regions support the hypothesis of short-durating and intermittent glaciations with several refugia. Several endemics are also found along the Jenisei and partly the Khatanga. Many border occurrences are found along the lower reaches of Jenisei and Khatanga.

The islands of Severnaya Zemlya are high-arctic, species-poor, and may be without distinguishing floristic elements.

Anabar – Olenyok (Ao)

This is a Siberian lowland region between the Khatanga River in the west and the Lena River in the east, including the Lena River delta. In the Khatanga drainage the boundary is drawn north of Khatanga town, in the Lena drainage between the villages of Kyusur and Chekurovka. The region has not been glaciated to any significant extent during the Pleistocene.

Due to the topography, the Anabar – Olenyok region is generally poor in species, and especially in diagnostic and endemic elements, compared with Taimyr in the west and Kharaulakh in the east, perhaps also less well investigated. There are some connections to the Central Siberian highlands and in addition a strong floristic element that follows the Khatanga, Olenyok, and Lena rivers where many border occurrences are found along their lower reaches. A few endemics are found along the Khatanga and especially along the Lena.

Kharaulakh (Kh)

Kharaulakh is a very small Siberian region that includes the northernmost extension of the Verkhoyansk Mountains along the right bank of Lena River, continuing in the Kharaulakh Mountains northwards to include the Tiksi area and the west side of Buorkhaya Bay.

The region has not been glaciated during the Pleistocene, except for small mountain glaciers.

This is a floristically strongly deviant and very species-rich region with a major connection southwards to the main mountain ranges of eastern Siberia. The number of endemics is much higher than in the more westernly regions and also much higher than in the Yana – Kolyma region bordering on Kharaulakh in the east. These endemics are partly connected to the Lena River valley, partly to the Verkhoyansk and Kharaulakh mountains. There are delimitation problems both along the Lena and in the mountains. In addition, the boundary in the Russian proposal (which we have accepted for the Checklist) is drawn about 100 km south of the actual polar treeline in the region. This means that we have had to include a very large element of borderline cases for this region (and for the Lena and Anabar rivers parts of Anabar – Olenyok).

Yana – Kolyma (YK)

This Siberian region includes the lowlands from the Tiksi – Buorkhaya area eastwards to the Kolyma River, and in addition the Novosiberian and Lyakhovsky island groups.

The region has not been glaciated during the Pleistocene.

This is a marshy, buggy, little investigated, and comparatively weakly characterized region but with some Beringian elements not known farther west, especially along the the Kolyma River. Some Siberian boreal elements follow the rivers northwards into the arctic parts, especially along the Yana, Indigirka, and Kolyma, but along the Kolyma River it is often difficult to tell from the Russian accounts on which side they have been found (i.e., whether they are in YK or CW).

The islands have a depauperate flora with few if any characterizing elements, or they may have been little explored.

West Chukotka (CW)

This Far East region east of the Kolyma River is often named Continental or North Chukotka. Compared with Yana – Kolyma, it is mainly mountainous except for a coastal plain around Chaun Bay. It includes the northern parts of the Anyui, Kolyma, and Anadyr mountains up to the watershed. The southern boundary is arbitrary and also problematic as we have applied a different criterion in the Brooks Range and the British Mountains on the American side.

The region has not been glaciated during the Pleistocene, except for local mountain glaciers.

This is the northern extensions of the major northeastern Asian mountain ranges and with a very strong and distinctive northeastern Asian floristic element, in addition to many amphi-Beringian taxa. The number of endemics is high. It is amply characterized floristically.

Wrangel Island (WI)

Wrangel Island and the nearby Herald Island, both ca. 200 km offshore, are considered, after discussion, as a separate Far East region. They are assumed to have been less affected by the Pleistocene glaciations than the mainland regions (but more affected by post-glacial submergence of the continental shelf).

The treatment of Wrangel Island and its taxa is strongly influenced by a hypothesis that this is the major part left of a large Pleistocene shelf area, now largely submerged, and that Wrangel Island perhaps has the strongest palaeo-element in the flora of the entire Arctic. Wrangel Island is recognized as a region in its own right mainly due to several endemic and disjunct taxa, partly connecting to the shelf areas of American Beringia. Some of the Wrangel Island endemics may, however, not survive a critical comparison with plants in other areas (also North America) where less narrow species circumscriptions have been applied. The alternative is to merge this region with West Chukotka. In any case, Wrangel Island is uncommonly species-rich (for an island) and with a species composition very different from the other islands and island groups north of mainland Asia. These other islands have no or almost no species distinguishing them from the nearest mainland areas, whereas Wrangel Island has numerous ones.

South Chukotka (CS)

This Far East region includes the southern part of the main Chukotkan mountains, the arctic parts of the Anadyr River basin, and the Koryak mountains and coast. Only smaller parts of it are defined as arctic, north and east of the woodlands and shrublands ('stlanik', i.e., Pinus pumila shrubs) in the Anadyr basin. It is more oceanic ('Pacific') than the other Russian Far East regions.

The region is assumed to have been unglaciated during the Pleistocene, except for local mountain glacier.

South Chukotka comprises three parts: (1) a coastal part of hills and mountains north of the Anadyr River estuary, inland including the floristically rich Pekulnei Mountains east of the Belaya River, (2) a coastal part bordering on the Koryak Mountains south of the Anadyr River estuary, and (3) a mountainous part north of the Anadyr River and west of the major northern tributary Belaya River. These three parts have different floristic compositions and each have their own endemic elements. Part (1) floristically combines Koryak coastal elements and more clearly Beringian ones from East Chukotka. Part (2) is the most oceanic and has major connections to the main Koryak mountains and coast and farther southwards to Kamtchatka. The southern limit on the Koryak Coast is arbitrary as the treeline is pushed southwards due to the oceanic climate. Part (3) is mainly intermediate between the boreal Anadyr River basin and the West Chukotkan Anadyr mountains in the north.

During the Checklist process it has been proposed to omit South Chukotka as a separate region and to assign part (3) to West Chukotka and parts (1) and (2) to East Chukotka. We retain it, however, as a separate region for the Checklist, mostly because the coastal parts are comparatively rich in plants with a Koryak – Kamtchaktan Pacific connection not found elsewhere in the Arctic.

East Chukotka (CE)

This Far East region has also been named Beringian Chukotka and consists of the Chukchi Peninsula (including Big Diomede Island), areas west of the Amguema – Paljavaam rivers, and an area around the northern parts of Anadyr Bay.

The region is assumed to have been unglaciated during the Pleistocene, except for local mountain glacier.

East Chukotka has the strongest Beringian (and American) element of all Russian regions, a large number of regional and local endemics, and is well characterized floristically. However, a merger across the Bering Strait with Western Alaska has been discussed during the Checklist process. The eastern Chukchi Peninsula is floristically very similar to the Seward Peninsula and other parts of western Alaska. A merger into one region across the Bering Strait could be justified, but then it would be difficult to draw its western limit towards the more 'Asian' parts of Chukotka. There are numerous, and partly common, plants that differentiate between East Chukotka and western Alaska, justifying two regions.

For the Bering Sea islands, see the next region.

Western Alaska (AW)

This U.S. region includes the parts west of the treeline in coastal western Alaska from north of Cape Constantine on Bristol Bay in the south, including the southwestern extensions of the Kuskokwim Mountains, across the Yukon River Delta to Saint Michael on Norton Sound, the Seward Peninsula west of Moses Point, the Kotzebue Sound area, and all areas west of the treeline and crossing the western Brooks Range (west of about 159–160W) north to Icy Cape on the Arctic Coast. In the southwest, the delimitation towards more oceanic areas is arbitrary because of the southwards push of the treeline by the oceanic climate. However, our delimitation is very close to that applied by Löve and Löve (1975a) and by Yurtsev (1994). The limit towards northern Alaska–Yukon (AN) at Icy Cape and in the Brooks Range is also quite arbitrary.

The region is assumed to have been unglaciated during the Pleistocene, except for local mountain glacier.

This is the American region with the strongest Beringian (and Asian) element. It clearly connects to the Chukchi Peninsula floristically, and some authors (e.g., Hultén) considered these two parts of one phytogeographical region. There are, however, some distinct floristic differences between the two sides of the Bering Strait even if the isolation is less than 10,000 years old. The number of regional and local endemics is high.

Two parts of the region cause borderline problems: the Yukon River Delta where the boundary is drawn very arbitrarily, and the southernmost coast along Bristol Bay which is reached by numerous American Pacific plants absent elsewhere in the Arctic.

The Checklist deviates from Yurtsev's (1994) original proposal in the treatment of the northern Bering Sea islands: St. Matthew, St. Lawrence, and the Diomedes. Yurtsev considered these a separate floristic region. An Aleutian – Bering Sea insular region could be justified floristically, including the non-arctic Commander, Aleutian, and Pribilof islands and the arctic ones mentioned above as its northernmost extension. However, in themselves the arctic islands are weakly and negatively characterized compared with the mainland on both sides, probably with less than 5 exclusive taxa. We have decided to apply the same principles here as for two other mainly negatively defined island areas: Jan Mayen in the North Atlantic and Franz Joseph Land in the Barents Sea. However, this comparison is not well justified because whereas Jan Mayen and Franz Joseph Land have no more southern connection, the arctic Bering Sea islands have their obvious connection to the more southern, non-arctic Pribilof and Aleutian islands. Together these island groups are well justifiable as a floristic region with an arctic extension.

For practical reasons, we have included the American islands in Western Alaska, the Russian Big Diomede Island in East Chukotka. The problem with this solution is that the boundary between the regions along the Bering Strait becomes fully artificial, more so than most of the other boundaries. It runs between the botanically very similar Russian Big Diomede and American Little Diomede. Also St. Lawrence Island has some Asian element absent from the Alaskan mainland.

Northern Alaska – Yukon Territory (AN)

This joint U.S. and Canadian region includes in Alaska the areas north of the treeline in the Noatak River valley, the Brooks Range, and the Alaskan Arctic Slope and Coast, in Canada the areas north of the treeline in the British and the northern Richardson mountains in the Yukon Territory and the westernmost Northwest Territory. The eastern boundary runs along the woodland limit in the eastern foothills of the Richardson and British mountains, which means that the unforested parts of the Mackenzie River Delta and plain are included in the next region. This is a deviation from the principles applied in Siberia.

The region is assumed to have been unglaciated during the Pleistocene, except for local mountain glacier.

The Beringian element is strong and distinguishes this region floristically from the region Central Canada as it shows a very marked decrease when crossing the 'Mackenzie Line'. The Cordilleran element is also strong and characterizes this region compared with both Western Alaska and Central Canada. The number of regional endemics is comparatively high, but there is also a number of lowland and coastal endemics shared with the northwestern Canadian islands. We suspect that these may be remains from a more continuous range on the now largely submerged 'Pleistocene shelf'. Comparatively many borderline occurrences are found in the Brooks Range where it is difficult to draw a boundary due to the long and deep valleys running in a S–N direction.

Subdivision of non-Beringian arctic Canada

The subdivision of non-Beringian arctic Canada (and partly Greenland) has been much discussed during the Checklist process. Yurtsev's original proposal was to recognize four regions: (a) a northwestern region of 'Central Canada' for the arctic mainland parts of the Northwest Territories and Nunavut east to the western Boothia Peninsula and for the islands east to and including Somerset, westernmost Devon, and Ellef and Amund Ringnes; (b) a region of 'West Hudson' of mainland Nunavut (previously District of Keewatin) from the eastern limit of region (a) to the middle of Hudson Bay and including Southampton Island, the Melville Peninsula, and northern Baffin Island; (c) a region of 'Baffin – Labrador' including the mainland areas east of the middle of Hudson Bay and southern Baffin Island; and (d) a region 'Ellesmere' of central and eastern Devon, Axel Heiberg, and Ellesmere islands. The arguments for this division were, among others, that Atlantic elements disappeared some distance west of Hudson Bay, that very few Beringian elements reached the west coast of Hudson Bay, that the areas east of Hudson Bay had a combination of Atlantic and eastern American elements absent from the areas west of Hudson Bay, and that there was a small endemic element centered on Ellesmere and Devon islands.

Canadian arguments against this division were, among others: (1) The line between Yurtsev's 'Central Canada' and 'West Hudson' runs through a floristically homogeneous area both on the mainland and in the islands. (2) The line between 'West Hudson' and 'Baffin – Labrador' in the middle of Hudson Bay divides on two regions a strong floristic element connected to the islands, shores and lowlands of Hudson Bay on both sides, and that the same line in Baffin Island is without phytogeographical significance. (3) The division is based on an evaluation of (amphi)Beringian and (amphi)Atlantic elements without taking into account that a major part of the North American flora is North American, not consisting of transgressing Asian and European taxa. Canadians proposed not to subdivide arctic Canada (except for the 'Mackenzie line'). This solution would give an unwanted imbalance in size and variation among the regions on the North American and on the Eurasian sides as there are fairly evident differences between the western islands (with "Beringian shelf" taxa), the central islands, the eastern Baffin Island (with "Atlantic" taxa), and perhaps the northeastern islands bordering on Greenland.

There might be some useful evidence for recognition of floristic regions in assumed past refugia and migration routes. The western Cordilleras (the Rocky Mountains and other ranges) contribute a significant floristical element which, together with Beringian refugial taxa, justifies separation of the Western Alaskan and the Northern Alaskan – Yukon Territory regions from all other parts of arctic North America.

Four possible refugial areas have been identified or indicated in the non-Beringian parts: (A) The Mackenzie River basin with a lowland element transgressing the arctic boundary in the Mackenzie Delta. (B) A refugial shelf area that connects the westernmost islands western Banks and Victoria, partly also Melville and Prince Patrick and the western mainland coast as far east as to the Liverpool Gulf in Nunavut. (C) A possible northern island refugium that consists of the Parry and Sverdrup islands and which might stretch to northern Greenland. (D) A possible source area connected to the eastern Cordilleras ('Appalachian') at least from New Hampshire to Labrador. In addition, the Hudson Bay lowlands and Ungava is very strongly influenced by an influx of boreal to low-arctic and generally North American taxa.

The Checklist solution is a compromise and is probably unsatisfactory for almost all participants. Some comments are given for each region below.

Central Canada (CC)

This Canadian region includes the mainland from (and including) the Mackenzie River plain in the west (NWT) to Melville Peninsula (Nunavut) and approaching Hudson Bay in the east, and the Canadian Arctic Archipelago except for the southernmost part of Baffin Island south of Cumberland Sound (included in Hudson Bay – Labrador) and Devon and the eastern Sverdrup islands (Axel Heiberg, Ellesmere, included in Ellesmere Land – Northern Greenland). The southern boundary runs across the outer parts of the Mackenzie River Delta north of Inuvik and then eastwards to Tuktut Nogait N.P. and north of Great Bear Lake, and in mainland Nunavut from Tuktut Nogait and northeast of Great Slave Lake to west of Hudson Bay north of Churchill (Manitoba).

The larger parts of this region have been glaciated during the Pleistocene, also during the last glaciation, but probably unglaciated or only intermittently glaciated areas are found in the western islands (parts of Victoria and Banks, perhaps also of Melville and Prince Patrick), on the mainland eastwards to the eastern Amundsen Gulf, and perhaps in the Mackenzie River Delta (and remains of previous shelf areas). Present-day glaciation is almost absent, even in the high-arctic islands.

As now circumscribed, the region is fairly 'natural' on the mainland but problematic in the islands. The western larger islands (especially Banks and Victoria) and the mainland areas east to Cape Bathurst deviate from the main central body by having an assumed relictual element that may have an origin on the Pleistocene shelf. This element includes some endemics. The line across Baffin Island is more of a south – north boundary than anything else, i.e., zonal. The separation of Devon and the eastern Sverdrup islands from the others is based on few criteria and is also partly zonal.

The Mackenzie River Delta is a major area of borderline occurrences, partly also with local endemics but at fairly low rank. Many borderline taxa occur close to Great Bear Lake.

Hudson Bay – Labrador (HL)

This Canadian lowland region consists of the shores and islands of Hudson Bay, including Southampton Island and the small surrounding islands, the Ungava Peninsula, the northernmost Labrador Peninsula, and the southernmost Baffin Island. On Hudson Bay, we include as arctic also the southern shores (in Manitoba, Ontario, and Quebec) from Churchill east to northeast of Belcher Island (but exclude James Bay), in Quebec the Ungava Peninsula north of Minto Lake (but exclude the head area of Ungava Bay), and in Labrador the northernmost tip north of Hebron. In Baffin Island, the parts south of a line from south of Cumberland Sound to Foxe Basin are assigned to this region. The delimitation in the south corresponds to the treeline but with problems on Hudson Bay and perhaps in the more oceanic parts of eastern Labrador. This delimitation largely corresponds to that proposed by Yurtsev (1994).

This region has probably been entirely glaciated several times during the Pleistocene, also during the last glaciation, and no refugial areas have any strong support. The Laurentide ice sheet was at its thickest in this area and remained her for longer than elsewhere. Due to this, the Hudson Bay lowlands were submerged for a long time after the last glaciation and is still raising fairly rapidly. There is no significant present-day glaciation.

The boreal American influence is stronger in this region than in any other, in addition to some eastern Cordilleran influence in Labrador. The most problematic part of this region is Hudson Bay and its climatic effect. The forest reaches a fair distance north along Hudson Bay on both sides. However, there is a narrow non-forested coastal strip along almost all of the southern shore due to the summer cooling of the sea ice and the cold water. The alternatives are either to draw a boundary line across the bay between the treelines on the two sides (as done by Löve and Löve 1975a) or to accept the southern non-forested coast as arctic. We have followed the latter course for the Checklist, but this results in an extreme concentration of borderline arctic occurrences along southern Hudson Bay due to the very sharp gradient from arctic waters and shores to boreal and forested inland. In addition, there are some Hudsonian endemics, probably of a young age, connected to the still rising shores of the Hudson and James bays.

Ellesmere Land – Northern Greenland (EP)

This trans-national region includes the Canadian islands of Devon (central and eastern parts), Axel Heiberg, and Ellesmere, and the northernmost parts of Greenland north of Melville Bugt in the west and north of the glaciers between Germania Land and Lambert Land in the east.

The region has been extensively glaciated during the Pleistocene and largely still is, both in Greenland and in Canada. However, it is situated at the northern rim of the ice shield during the last glaciation. Refugia have been proposed both in Ellesmere Island and in northern Greenland but are disputed.

The gap between Ellesmere Island and northwestern Greenland is narrower than between many of the larger Canadian islands and is even today ice-covered most or all of the year. The phytogeographical connection is very close, and a common refugial history is indicated. A small endemic element, mostly at subspecific level, is suggested (e.g., in Braya and Puccinellia), especially in Ellesmere. Even if most parts of the region is high-arctic, interior parts of Ellesmere Island have a remarkable favourable climate and a rich flora compared with other areas at 80N.

Western Greenland (GW)

This region includes western and southernmost Greenland, in the south delimited towards eastern Greenland along Lindenow Fjord in southeastern Greenland.

The region has been extensively glaciated during the Pleistocene, and still is. Whether there may have been refugial areas (or nunataks) is undecided.

All the Greenland forest enclaves are located in Western Greenland as here delimited. In spite of these, we consider all of Greenland as arctic. The very few taxa restricted to the small inland forested enclaves in the southwestern parts are included in the Checklist but with notes on their borderline character. This is an important deviation from Yurtsev (1994) as he excluded all of southern Greenland from the Arctic.

Floristically, western Greenland is connected westwards to Canada, partly also southwestwards to the eastern Cordilleras and Labrador – Newfoundland. There is, however, a fairly distinct local (endemic) element that characterizes it relative to the Canadian regions and also differentiates it well from eastern and northern Greenland. This may suggest refugial situations.

Eastern Greenland (GE)

This region includes eastern Greenland south to Lindenow fjord. It is thereby isolated from northern Greenland by large glaciers running into the sea and from western Greenland by the Inland Ice Cap. The transition in the south, around Lindenow Fjord, is more gradual.

Eastern Greenland has been extensively glaciated during the Pleistocene and still is, even more than western Greenland. Whether there have been refugial areas (or nunataks) is undecided.

The region is floristically distinctly closer connected to Europe and to the Eurasian Arctic than is western Greenland and also northern Greenland (except for the connection to Svalbard). There is a small element of endemics, all probably of hybridogeneous and recent origin. Some other elements connect clearly to western Europe (e.g., Ophioglossum azoricum and Polygala serpyllifolia). Some isolated occurrences of Asian species not found in northwestern Europe (e.g., Draba sibirica and Potentilla stipularis) may suggest refugial situations, especially in the northern parts.

2.3 Vegetation zones

The vegetation zones reflect the mainly thermically determined changes from south to north. The criteria are summarized by Elvebakk (1999). We have found a division into five zones practicable, where each of the zones reflects an approximately 2C decrease in mean temperature for the warmest month from ca. 10C at the thermic treeline to less than 2C in the northernmost zone. The zones are named differently in different traditions. For the Checklist, we have decided to design them in the distribution tables just with letters, from A (the northernmost) to E (the southernmost), but below are also included the three name proposals by Elvebakk (1999, as a-c) and the names proposed by Yurtsev (1994, as d). The first name proposals (a) are the ones preferred by the majority of the Editorial Board and are emphasized. The occurrence of zones in the 21 floristic regions is shown in Fig. **. Internal note: Figure and figure number to be included.

Zone A

a) Arctic polar desert zone; b) Arctic herb zone; c) Northern high-arctic zone; d) High-arctic tundras.

Mean warmest month temperature less than 2C. Sparse (open) vegetation of forbs and graminids, more abundant mosses and lichens. Woody plants are (nearly) absent. The species diversity is low and probably no phanerogam is exclusive to this zone. During the postglacial warm period (the 'Hypsithermal'), this zone may have been nearly obliterated, which may explain its lack of specific characterizing vascular plant species.

We apply the 'polar desert' concept differently from how it often is applied in North American literature. We refer to thermic conditions alone, not to open or very depauperate vegetation which may be caused by unfavourable substrate (limestone). We therefore do not include the widespread "limestone deserts" in the Canadian Arctic Archipelago in the Arctic polar desert.

The zone is present in Svalbard, Franz Joseph Land, northern Novaya Zemlya, Severnaya Zemlya, and as a very narrow zone on mainland Taimyr Peninsula (see Razzhivin 1999), in the northwestern Canadian Arctic Archipelago, in northernmost Ellesmere Island, and as a narrow zone in northern Greenland. Note that the zone is absent from arctic Russia east of Taimyr and from arctic America west of the Canadian Arctic Archipelago, i.e., from all of 'Mega-Beringia'.

Zone B

a) Northern arctic tundra zone; b) Arctic prostrate shrub zone; c) Middle high-arctic zone; d) Northern arctic tundras.

Mean warmest month temperature ca. 2–4C. Mostly open vegetation of forbs, graminids, prostrate or 'subterranean' shrubs (Salix polaris), and often luxuriant moss and lichen vegetation. The species diversity is much higher than in zone A but still low. Very few if any species are restricted (endemic) to the zone but some arctic endemic species reach it. This zone may also have been much depauperated during the postglacial Hypsithermal.

The zone is present in Svalbard, Novaya Zemlya, some narrow mainland coasts in western Siberia eastwards to Taimyr, the Novosiberian Islands, the Lyakhovskiy Islands, perhaps a small part of Wrangel Island, northern parts of the Canadian Arctic Archipelago, and Greenland,. Also this zone is largely absent from 'Mega-Beringia'.

Zone C

a) Middle arctic tundra zone; b) Northern arctic dwarf-shrub zone; c) Southern high-arctic zone; d) Southern arctic tundras.

Mean warmest month temperature ca. 4–6C. Open to often closed vegetation of dwarf-shrubs, prostrate shrubs, graminids and forbs, often also cryptogam-dominated. The species diversity is comparatively high (the increase from zone A to zone C is much steeper than from zone C to zones D and E). There are several species endemic to this zone.

The zone is present in Jan Mayen, Svalbard, Bear Island, southern Novaya Zemlya, Vaigach, the majority of Russian mainland regions from Yugorskiy Peninsula eastwards to West Chukotka and Wrangel Island, the northernmost tip of Alaska, most parts of the Canadian Arctic Archipelago, mainland Canada from Boothia Peninsula to the tip of Ungava Peninsula, and central Greenland.

Zone D

a) Southern arctic tundra zone; b) Southern arctic dwarf-shrub zone; c) Northern low-arctic zone; d) Northern hypoarctic tundras.

Mean warmest month temperature ca. 6–8C. Closed vegetation with dwarf-shrubs and graminids as predominant elements, low thickets (Salix, Betula nana, Juniperus communis) and marshes. The species diversity is not very much higher than in zone C, probably partly due to more competition in the denser vegetation cover. A number of endemics are found but few are restricted to this zone.

The zone is present in all of mainland Russia from the Pechora area (and northern Kolguev Island) eastwards to East and northern South Chukotka, northern parts of western Alaska and much of northern Alaska, in Canada in southern Banks and Victoria islands and much of the arctic mainland, southernmost Baffin Island, and central to southern Greenland.

Zone E

a) Arctic shrub tundra zone; b) Arctic low-shrub zone; c) Southern low-arctic zone; d) Southern hypoarctic tundras.

Mean warmest month temperature ca. 8–10C. Closed vegetation where mires, heaths and thickets of erect shrubs (mainly Salix, Betula, Alnus) often dominate. The total species diversity is much higher than in zone D, mainly due to transgression of otherwise boreal taxa into this zone and in some regions also of taxa from neighboring mountains. The boreal transgressions may partly be remains from the postglacial Hypsithermal. Mountainous areas in this zone in northern Asia and northwestern North America have the highest number of endemics in the Arctic.

The zone is the only one present in Iceland, mainland Norway, the Russian Murman area, and occurs all the way farther eastwards to South Chukotka (but mapped as very narrow to nearly absent in much of Siberia), in most parts of western Alaska and all of the Brooks Range in northern Alaska and the British Mountains in northwestern Canada, as a broad zone in mainland Canada and as a very narrow zone along Hudson Bay, on the eastern Canadian peninsulas, and in southern Greenland.

In the distribution tables are also included occurrences in immediately neighboring boreal and alpine areas (as N).

The floristic regions and the bioclimatic zones are combined in the following way in the table below: *** – constitutes a major part of the region (50 % or more); ** – constitutes a moderate part (20–50 %); * – constitutes a smaller part (less than 20 %); x – bordering on the boreal. Zones: A – Polar desert, B – Northern Arctic, C – Middle Arctic, D – Southern Arctic, E – Shrub tundra, N – Boreal and/or Boreal – Alpine. The isolated occurrence of zone C in the region Northern Iceland (Ic) is due to the island of Jan Mayen.

N Iceland (Ic)x****
N Fennoscandia (FN)x***
Kanin – Pechora (KP)x*****
Svalbard – Franz Joseph (SF)*******
Polar Ural – Novaya Zemlya (UN)x*********
Yamal – Gydan (YG)x*******
Taimyr – Severnaya Zemlya (Tm)x**********
Anabar – Olenyok (AO)x*******?
Kharaulakh (Kh)x****
Yana – Kolyma (YK)x*******
W Chukotka (CW)x*******
Wrangel I. (WI)****?
S Chukotka (CS)x*****
E Chukotka (CE)*****
W Alaska (AW)x*****
N Alaska – Yukon (AN)x******
Central Canada (CC)x*********
Hudson – Labrador (HL)x******
Ellesmere – N Greenland (EP)******
W Greenland (GW)********
E Greenland (GE)********

3 Arctic vascular plants

3.1 Natives and adventives

Some scientists consider the Arctic a predominantly virgin environment. Others assume that it has been strongly influenced by human activities like all other parts of the globe. Both views are right. However, for vascular plants the former viewpoint is closer to the truth as shown by the following three features:

(A) As far as we know, no single predominantly arctic vascular plant species has gone extinct due to human activities in the last 250 years (and most probably not earlier either). This is not only true for the Arctic in general but probably for each of the six countries involved.

(B) Neither is the Arctic strongly influenced by 'aliens', i.e., plants with their origin elsewhere but spread to the Arctic through human activities. The total number of alien plant species with stable presence in the Arctic (and included in the Checklist) is low and their proportion of the flora of each region is low to negligible. With a significant exception, the adventive plants are confined to settlements and their close surroundings, trading posts, mining areas, airstrips, harbours, and the few roads and railways. They are not considered a danger to the native flora. The exception is the plants introduced with agriculture in the North Atlantic regions. Here there have been (present or past) agricultural settlement for a thousand years or more and these have made a great impact on the local and regional floras. This concerns southwestern Greenland and Iceland with Norse settlements in Medieval times, in Iceland until today, northern Norway with settlements back to the Iron age, perhaps even back to the Bronze Age, and in some northern European Russian areas with more recent agricultural settlement. In these regions, agricultural archaeophytes have been a significant part of the now long established flora for more than a millennium, i.e., probably the same duration as for some natives.

Except for these archaeophytes, the absence of aggressive immigrants into the Arctic is due to the possible immigrants being adapted to much more favourable conditions, climatically and otherwise. This situation may change if the global temperatures continue to raise.

(C) The 'original' phytogeographical pattern is intact in the Arctic. There are few, if any, documented case of spread of plants by man between arctic regions. In temperate areas, such spread is now disturbing and obscuring the natural patterns and makes a distinction between non-anthropogenic and anthropogenic plants practically impossible in many regions. There has been frequent travel between some arctic regions, especially between Alaska and Chukotka, between Russia, Norway, Svalbard, Greenland, and Iceland, and between Greenland and Canada, but we know of no substantiated case of arctic trans-regional anthropogenic dispersal of native species. A few cases have been proposed between Scandinavia and Greenland (e.g., Astragalus alpinus, Carex rostrata, and Leymus arenarius), between Scandinavia and Svalbard (several, e.g., Saussurea alpina), and between Russia and Norway (e.g., Alopecurus arundinaceus, Conioselinum tataricum, and Stellaria hebecalyx), but the possible source areas of these plants are boreal, not the Arctic.

Together these three features make the Arctic a virtually virgin field for studies of the influence of non-anthropogenic processes on phytogeographical patterns from the Tertiary to the present. This will, however, probably not last. Anthropogenic climatic change, 'modernization' of the communities of its native peoples, and increased use of the Arctic for recreation, research, and for extraction of its mineral resources, will by necessity influence its flora and phytogeographical patterns. In a recent, unpublished study (I.G. Alsos, pers. comm.), it was shown that each visitor from abroad to the high-arctic Svalbard islands by a mean carried viable seeds on their shoes, the researchers more than the tourists. The Checklist may therefore be a reference point before this process accelerates.

The records in the Checklist are therefore separated on three categories based on whether the taxa are considered as native or as anthropogenic and on whether they are persistent or not in the Arctic:

(1) Records as native. These include plants we assume to have reached the Arctic by non-anthropogenic means and plants brought to the Arctic by pre-Medieval activities of native people or early agriculturalist. For these plants, all occurrences we know of are included in the Checklist, also casual occurrences due to 'natural' means (assumed transported by, e.g. birds or sea currents). These 'native casuals' are too few to warrant separate consideration: Suadea (probably) in the Russian Far East, Cakile in Svalbard and perhaps in southern Greenland, Atriplex in Bear Island, Gnaphalium in western Greenland, and perhaps a very few others.

(2) Records of persisting adventives. These include plants assumed brought to the Arctic by man's activities from Medieval times onwards and now self-sustaining in their arctic sites by vegetative means or by seed (or spore) reproduction for at least two generations. The principle has only been possible to follow in the past and present agricultural areas of Greenland, arctic Iceland and Norway, and arctic northwestern European Russia, and in the comparatively few places elsewhere in the Arctic where there is permanent settlement and where botanists go fairly often, mainly in Nome and some other settlements in western and northern Alaska, some sites on the southern shore of Hudson Bay, numerous places in Greenland, and a few in Svalbard. For the Russian parts it is mainly guesswork, but guesswork based on what we know generally about the ecological and reproductive requirements of the relevant taxa. We have included rather than excluded dubious cases. This means that perennial taxa with some means of vegetative persistence in the places where they have been introduced ('remaining' taxa) usually have been included, whereas annuals and biennials with comparatively high thermal requirements for reproduction and perennials without vegetative spread have been excluded. The persistent adventive plants are – almost without exception – confined to past or present settlements or trading posts. We know of no single case where they have had an extensive spread from their assumed places of introduction, except for a few recent and probably not fully persistent occurrences on road verges and along railways.

(3) Records as casual adventives. Casuals are quite frequent in some arctic settlements, sometimes very far to the north. Due to the relative density of settlements, and the frequent communication with Denmark, a high number of such exotics are recorded for western and southwestern Greenland, much higher than in, e.g., the villages and farming areas of northern Iceland or northernmost Norway. The reason is probably that the Greenland communities have been and are much more dependent on import than the more self-sustaining fishing and farming communities in Iceland and Norway. Some other hot-spots of exotics are also fairly well documented, especially Nome in western Alaska, Churchill (railroad endpoint) on Hudson Bay, the Vorkuta area (railroad endpoint) in European Russia, the Dudinka area at the lower Jenisei River and Tiksi close to the Lena River Delta in Siberia, and the townships of Anadyr and Provideniya in the Russian Far East. A similar situation to that in Greenland is evident in the large industrial and communication settlements in arctic Russia, especially Vorkuta, Norilsk – Dudinka, Tiksi, and Provideniya, nearly totally dependent on imports for their existence. Even in the five high-arctic Russian and Norwegian mining settlements in Svalbard (at 78–79N) are records of, e.g., sunflowers, peas, plums, apples, and pears, and of a few for these latitudes quite exotic weeds (e.g., Atriplex sagittata and Medicago polymorpha) scarcely recorded as persistent even in boreal northern Europe. For the main parts of the Checklist (text and tables), casual records are only included for plants that are documented or assumed to persist in at least one arctic region. We have not been able to make a full survey of casual records, but those we have come across are listed and commented on in a separate chapter below (Casual taxa).

3.2  Occurrences in the Borderline Arctic

The southern boundary of the Arctic is 'fuzzy', both in nature and in our treatment. The treeline is an important ecological boundary and numerous species reach or very often slightly cross this line. A high proportion of the taxa that reach the northern boreal zone therefore have some recorded occurrences in the Arctic. More diffuse is the arctic boundary in the treeless coastal regions bordering on the North Pacific and the North Atlantic. We have been fairly liberal in inclusion of plants that only occur at our boundary, also to be prepared for future mapping of changes, e.g., northwards spread of (comparatively) thermophilous plants. Plants that occur at or very close to the southern boundary of the Arctic are therefore consistently included but indicated as 'borderline' (main text) or marked as 'b' (distribution table).

The number and 'quality' of borderline records that we have accepted vary between regions. In Greenland there are none as all of Greenland is considered arctic. In Iceland, mainland Norway, and the Murman area, the arctic boundary is fairly exactly drawn, and the plant distributions well recorded (for Iceland Kristinsson 2010, for Norway the herbarium databases, for Fennoscandia including the Murman area, e.g., Hultén 1971b, for the Murman area in more detail Gorodkov and Pojarkova 1953–1966). In these regions the indicated occurrences in the Borderline Arctic are real.

Farther east in Russia the boundary is less well defined and less exactly drawn and the floristic mapping of records also less exact. There are many discrepancies among different sources, e.g., when comparing Tolmachev (1974–1977, northeastern European Russia), Tolmachev and Yurtsev (1960–1987, the Russian Arctic), Krasnoborov et al. (1988–1997, Siberia), Kharkevicz (1985–1996, the Russian Far East), and Hultén and Fries (1986, the entire circumpolar area). The main initial Russian input to the Checklist has been from the scientists of the Komarov Botanical Institute in St. Petersburg, and the St. Petersburg records are also the base of the checklist of Sekretareva (1999, 2004), but very often different data and different interpretations have been presented by the research groups in Siberia and the Russian Far East. We assume that the differences are due to consulting and basing their maps on different sources (e.g., herbaria) and not utilizing all the available sources. Resolving such inconsistencies must be the responsibility of the Russian scientific community.

Within Russia we have adhered strictly to the arctic boundary as proposed by Yurtsev (except for the westernmost parts which he did not consider as arctic. We have therefore included as borderline cases many taxa stated by the Russian botanists as 'not arctic'. We agree with their interpretation of the majority of these taxa, but as long as there are records of them at or north of the boundary as drawn by Russians, we can not exclude them. This implies an uncommonly large number of borderline cases along major Russian rivers, especially the Pechora, Ob, Jenisei, Lena, Kolyma, and partly Anadyr. In most or all of these cases, the arctic boundary should probably have been drawn farther north along the rivers than in the surroundings (as is done along, e.g., the Mackenzie River in Canada). We have observed that the true (and sharp) Larix treeline along Lena River runs ca. 100 km north of the boundary as drawn in the Russian proposal.

In North America, the boundary follows the treeline except for the oceanic regions of southwestern Alaska and northeastern Labrador, but the number of borderline cases is still probably too high in some regions due to records being less exactly mapped. The boundary southwest of the Kuskokwim Mountains in Alaska is especially arbitrary and also important because this is an area with very numerous northern extensions of Pacific species. The number of borderline cases would be high wherever we drew the line. Similarly, the inclusion of all of the Brooks Range and the Philip Smith, British, and northernmost Richardson mountains north of the treeline results in quite numerous slightly transgressing boreal and Cordilleran plants as borderline cases. The lower Mackenzie River poses the same problem as the large Siberian rivers, but here our boundary is drawn at the northern treeline. Still, the Mackenzie River Delta is a hotspot of borderline arctic taxa. The arctic boundary in non-forested Labrador is drawn straight to the sea from the inland treeline and is therefore arbitrary. Still, there are much fewer borderline cases here than in other coastal areas, mostly due to the species-poor flora.

The absolutely highest number and relative amount (percentage) of borderline arctic taxa for any region in the Checklist is recorded at Hudson Bay, ca. 65 taxa. The real number may be even higher as taxa with proven occurrence at the coastline of the bay are entered by us as 'rare' and not as 'borderline'. Exclusion of the southern Hudson Bay coastline from the Arctic as circumscribed would probably reduce the arctic flora as treated by the Checklist by close to 100 taxa. At the same time, this is an area with extensive marshes and shores dominated by otherwise arctic species (and a heavy concentration of Polar Bears) and is seen as truly arctic by most visitors. We have to accept that this is a region where the Boreal and the Arctic overlap more extensively than perhaps anywhere else in the Arctic.

3.3 Taxonomic categories

The Checklist consistently applies the following categories: family, genus, species, and race (subspecies / variety). Infrageneric categories (i.e., categories between genus and species) are included more sporadically and mostly due to some practical reason. Hybrids are only included when some independence from their parents is assumed (see below).

Families. Families of angiosperms and gymnosperms follow APG2 (Stevens 2001 onwards, Angiosperm Phylogeny Website), with one or two exceptions. Also the order of families follows APG2. For pteridophytes, a more informal order is applied. Internal note: Change to APG3, at least as concerns the pteridophytes and gymnosperms.

Genera. We have recognized genera more narrowly than in many current regional treatments. Here we have often taken into account recent molecular and phylogenetic studies. Revisions of generic limits appear very frequently in the literature today, and the genera may change appreciably until a Panarctic Flora is realized.

Infrageneric categories. Such categories are only included in the Checklist in a few genera with numerous species and only where they can be of some use and can be applied more or less unambiguously. This is in contrast with many Russian treatments, where a major focus in later decades has been on infrageneric classification, and with the Flora of North America treatments. Our approach is more in accordance with, e.g., the Flora Europaea tradition where these categories were applied most sparingly. It is often problematic to decide where an infrageneric classification is relevant, and there are many cases in the arctic flora where there seems to be even more disputes about these categories than about genera and species. One explanation may be the modes of speciation in the northern regions. If allopolyploid speciation is prevalent among arctic vascular plants, as many scientists assume, the higher ploidy levels may be based on crosses between diploids in different series, sections, and even subgenera. In such cases a subgeneric classification may be relevant for the diploids but less so for the often more numerous polyploids. There are strong indications of such reticulations in many large arctic genera like Draba, Oxytropis, Papaver, Poa, Potentilla, and Salix. Instead we often apply the informal category 'aggregate' where a common comment is given for a group of species.

Species (excluding agamospecies). As to species and also subspecies / varieties, there are many different traditions in how to handle these categories. The problems concerning arctic taxa are discussed in several contributions in Nordal and Razzhivin (1999).

In general, we probably circumscribe species more broadly in the Checklist than done in most previous (and some current) Russian treatments but more narrowly than in some current North American treatments. Species is applied for taxa differing more or less disjunctly from their assumed relatives in several (assumed) independently inherited characters, usually also with some (asssumed) reproductive barriers towards their relatives. The reproductive isolation is in most cases based on circumstantial evidence as very little factual evidence is available for the majority of arctic plants, even if the situation is rapidly improving. One important feature is that we consider sympatric but morphologically non-overlapping taxa as species rather than subspecies (as different from many Flora of North America authors). Another one is that we, in principle, consider hybridogeneous taxa as species in their own right, and not as hybrids, when they have an independent reproduction and sometimes also an independent range (i.e., more than a 'first' hybridization event or a hybrid swarm). This is the case both with hybridization products at the same ploidy level, where we demand some stabilization to have taken place, and with documented or assumed allopolyploids.

Geographical criteria have often been applied previously in many Russian treatments for separating closely related species and subspecies. Largely sympatric taxa (with strongly overlapping ranges) and fully allopatric taxa (disjunct or vicariant) have in these treatments mostly been accepted as species, whereas parapatric taxa (with partly overlapping ranges and often with intermediates in the zone of overlap) have been considered subspecies. These restrictions are not applied for the Checklist. We accept as species taxa in all the three categories of geographical pattern.

There are several problems with the reproduction criterion for species. Firstly, many arctic plants are inbreeders. It is more or less irrelevant or unknown whether they can or really do cross regularly. Secondly, there are indications that reproductive barriers may arise more rapidly when and where taxa are in contact than where they are not. From a 'biological species' viewpoint, the former should be species, whereas the latter could be races. Close to nothing is known about the potential or realized reproductive behaviour of the majority of arctic plants in this respect. For all practical purposes we have to rely on morphology and guesswork. A major part of the discussions among the PAF collaborators have concerned these matters. In most cases, the Russian participants have preferred treatment as species, the North American participants have preferred treatment as races or just as a collective species, and the Europeans have vacillated (e.g., in several groups of grasses, the Anemone narcissifolia group, the Astragalus australis group, Dryas, several groups in Oxytropis, some Antennarias, and the Arnica angustifolia group). But, there has also been several cases where Europeans and North Americans go for species and Russians for races or a collective treatment (e.g., Huperzia, the Epilobium davuricum – arcticum group, the Pedicularis sudetica group, and Pyrola rotundifolia s. lat.). Thirdly, there are major groups of arctic plants that reproduce asexually.

Agamospecies. Apomictic (asexual) reproduction is assumed mostly to result from initial hybridization and subsequent escape from hybrid sterility by asexual means. Large groups of arctic plants propagate mainly by asexual means. For these groups almost all the reproductive criteria for species recognition are irrelevant. These groups also differ among themselves in many other relevant aspects: morphological variation patterns, degree of apomixis (whether facultative or nearly obligate), degree of polyploidization, means of propagation, and the geographical patterns. The cases span from: (a) Occasional change to bulbil reproduction in otherwise sexual genera, e.g., Bistorta vivipara, Deschampsia alpina, the Festuca vivipara group, Huperzia, Micranthes foliolosa, and some Saxifraga spp.; (b) Occasional agamospermy in a single or a few species in an otherwise sexual genus, e.g., in Draba; (c) Complexes of sexual functional diploids, primary hybrids, and agamospermic functional polyploids ('functional' because the basic chromosome level in the genus may be, e.g., tetraploid or higher), e.g., Antennaria, Arnica, Calamagrostis, Erigeron, Pilosella, Poa, Potentilla, and Sorbus, in Poa also complicated by reproduction by bulbils; to: (d) Full-fledged, mainly polyploid agamospermic complexes with sometimes hundreds or thousands of described 'species' and with very few or no extant sexual species, e.g., Alchemilla, Hieracium s. str., the Ranunculus auricomus group, and Taraxacum. The amounts of such apomictic taxa are perhaps highest in areas strongly affected by the Pleistocene glaciations in temperate parts of Europe (there also with, e.g., Rubus and Sorbus) and North America (there also with, e.g., Amelanchier, Crataegus, and Symphyotrichum). This concentration is often interpreted as due to the disturbances and migrations over the entire continents during and between the glaciations. The percentage of apomicts among described taxa is, however, high throughout the entire Arctic.

The apomictic complexes have been treated in many ways throughout their systematic history. One approach has been to try to identify morphologically the 'smallest' entities and name them, mostly as species. This has resulted in description in the Nordic area alone of ca. 2000 species of Hieracium, ca. 400 species of Taraxacum, and ca. 400 species of the Ranunculus auricomus group, and from the rest of Europe several hundreds or thousands of species of the same genera and of Alchemilla and Rubus, among others. Other parts of the world have not had the same eager 'species-namers', but some North Americans working on Antennaria approach the Europeans in this respect. This approach is clearly non-functional from the viewpoints of biodiversity, conservation, and practicality. If these entities are considered as 'full' species, the absolute majority of named and geographically restricted, vulnerable or threathened 'species' on the European continent would be agamic microspecies of 5 or 6 genera, separable only by very minute criteria, and recognizable or recognized only by a few specialists, some of them now long dead.

Another approach was exemplified by Flora Europaea (Tutin et al. 1964–1980, 1993). In this Flora, the authors of these genera included the numerous microspecies in aggregates informally named as 'groups' or 'circle species', where a more widespread microspecies was selected as the descriptor of a group of similar but often more restricted microspecies. This approach has been followed in some Russian treatments of, e.g., Hieracium and Taraxacum but has been abandoned in the "follow-up" of Flora Europaea, the Atlas Florae Europaeae (see Kurtto et al. 2007 for Alchemilla). A third approach is exemplified by the North American treatments of Antennaria by Bayer and Chmielewski, merging the numerous described agamospecies into a few widely circumscribed species with subspecies, by Bayer also with separation of the assumed basal sexual taxa from the assumed derived agamic taxa as subspecies.

The situations in the different apomictic groups are too diverse to allow for a common approach. For the Checklist we have applied several approaches:

(a) In genera where there are just a few agamic taxa in the Arctic, separable from their sexual putative progenitors (extant or perhaps extinct) by sufficient morphological criteria, they have been treated just as the sexual species. Examples: Bistorta, Deschampsia, Erigeron, Saxifraga, Solidago, Symphyotrichum.

(b) In genera where there are at least some extant basal functional diploids and derived agamic polyploids of known or presumed known parentage, they have partly been treated as species, partly as races, depending on their morphological distinctness. Examples: Calamagrostis, Festuca, Pilosella, and also Antennaria which is a borderline case towards the next category due to its high number of described agamospecies.

(c) In genera or groups consisting predominantly or entirely of agamic taxa, and where very numerous agamospecies have been described, the Flora Europaea approach has been applied, grouping the named arctic microspecies into fewer 'collective species' comparable in morphological width and geographical range with sexual species, and with a much abbreviated listing of named microspecies: Hieracium s. str., the Ranunculus auricomus group, and Taraxacum. The exception is Alchemilla where the accepted arctic representatives are fairly easily recognized and entered in the Checklist as full species, even if this genus is a mess farther south, e.g., with 442 European agamospecies (Kurtto et al. 2007).

(d) For two partly apomictic genera – Poa and Potentilla – the PAF collaborators have had problems reaching a consensus proposal. In both cases the discussion has concerned the importance of hybridization in the origin of named taxa, i.e., whether the evolutionary pathways can be mapped with any certainty without genetic investigation (or even with genetic investigation), and whether it is worthwhile to describe, name, and accept numerous assumedly hybridogeneous agamic lineages as taxa. The analyses of the morphological variation in these genera – and speculations about its causes – have arisen at a much later stage than in some other agamic groups like Alchemilla, Hieracium, Rubus, and Taraxacum. We have at least to accept the historical importance of the 19th and early 20th century systematists describing the perhaps 5000–6000 'species' in these genera. We are more reluctant to do the same today. In parts of Poa, the discussion concerns whether three major mixed sexual and apomictic groups, partly with both agamic seed reproduction and with reproduction by bulbils, should be treated more collectively (as proposed by, e.g., Soreng) or with numerous species (as proposed by Tzvelev): the section Poa with the P. arctica group and the P. pratensis group, and the section(s) Stenopoa – Tichopoa. Parts of the Checklist entry for this genus is more or less disapproved by all PAF participants. In Potentilla, the situation is even more complicated as there is some experimental support for the hybridization / agamospermy model underlying the treatment of Soják and Yurtsev resulting in very numerous 'species', but there is reluctance on the part of at least Elven, Eriksen, and Murray to accept all the assumed hybridogenous products as stabilized and independent taxa. Also for this genus, all the PAF collaborators will (or would) disagree with a smaller of larger part of the Checklist entry.

Races (subspecies vs. varieties). The application of the racial categories of subspecies and variety differs among botanists in western Europe, Russia, and North America.

During the Komarov era (Flora URSS), Russian botanists mainly applied only the rank of species, often organizing closely related (or at least very similar) species into series. Afterwards they have often applied the rank of subspecies for parapatric, assumed interfertile taxa, whereas they have preferred to apply the rank of species for both sympatric and allopatric situations. This is a mainly geographically based criterion. The rank of variety is applied more sparingly and mainly for more local ecotypes or even modifications.

The majority of North American botanists currently engaged in the Flora of North America project apply the ranks of subspecies and variety as interchangeable. This has support in the current International Code of Botanical Nomenclature (ICBN Vienna Code, McNeill et al. 2006) where taxa similarly named at these two ranks are treated as homonyms. However, subspecies is considered as a 'higher' rank than variety (ICBN, Article 4.1), i.e., a subspecies may be divisible on two or more varieties if so desired. In the treatments published until now in Flora of North America, the application of either subspecies or variety depends on the preference of the author.

Western European botanists have mostly treated the two ranks of subspecies and variety as different, as exemplified by Flora Europaea (Tutin et al. 1964–1993), Flora Nordica (Jonsell 2000 onwards), Atlas florae europaeae (Jalas et al. 1972 onwards), and almost all regional floras (e.g., Elven et al. 2005 for Norway). The editors of Flora Europaea even made a decision in principle to include subspecies but exclude varieties. European authors then mostly apply the rank of subspecies to morphologically definable major geographical or eco-geographical races and sometimes for ecological races and ploidal races (assumed to have arisen through autopolyploidy) if they also can be morphologically characterized. The main assumption is that the two or more subspecies result from a split of one species but that the subspecies are not (fully) reproductivelly isolated from each other. The rank of variety is applied to taxa differing in few characters and often assumed ecotypical or results of very local divergence.

For the Checklist, we have to accept the names and ranks as published. This means that major races may be named as either varieties or subspecies depending on what names are available. For the major arctic race of Astragalus alpinus, we have to apply the name var. arcticus because the combination subsp. arcticus is illegitimate. However, if we have a choice, we apply a subspecific combination for (geographically) major races (e.g., Oxytropis deflexa subsp. retrorsa instead of var. sericea), whereas we apply a varietal combination for more local races, ecotypes, or in a few cases for taxa of uncertain rank (Artemisia globularia var. lutea instead of subsp. lutea, should be evaluated as possibly at species rank).

In practical cases, geographically and ecologically overlapping taxa that keep fairly distinct are treated as species, whereas extensively intergrading taxa are treated as races. See the notes to several species of Salix (e.g., S. bebbiana and the S. glauca, S. lanata, and S. phylicifolia groups). For geographically non-overlapping taxa, and for geographically overlapping but ecologically non-overlapping taxa, the criteria are purely morphological. If the taxa are morphologically very similar (differing in few characters) and assumed to have arisen from a common stock fairly recently without an assumed internal reproductive barrier (i.e., no assumed polyploidization etc.), they are mostly treated as races. Assumedly non-adaptive features are given more weight than assumedly adaptive ones in deciding between rank as species or race.

If different genomes are assumed involved (allopolyploidy), the normal category for the Checklist is species, but a major exception has been accepted in Antennaria, in lack of good alternatives.

The treatment chosen for the categories species, subspecies, and variety was decided initially in the PAF Checklist work (see Elven 1999): "Both species, subspecies and variety shall be viewed pluralistically, meaning that several different biological situations might be covered by each, based on different criteria. They are to be viewed as levels of differentiation only." and "Species, subspecies and varieties shall be based on morphological criteria. Available data on genetics, evolution, and reproductive system should be taken fully into account, but should not overrule morphological evidence." No evolutionary connection is assumed, i.e., we do not assume that variety is a developmental stage towards subspecies, or subspecies towards species. In some cases it may be so, in others not. If we were to start again today, we would probably go for a single subspecific category for geographical, eco-geographical, ecological, and ploidal races.

Hybrids and hybridogeneous taxa. Primary hybrids and hybrid swarms, even if named and accepted in regional Floras, are – as a rule – not accepted as taxa for the Checklist. Hybrids are only included where they have an internal homogeneity or an existence independent of their proposed parents, either by occurrence well outside the range of one or both parents or by independent propagation (sexual or asexual), or preferrably both. See, e.g., discussions in connection with Coptidium x spitsbergense, Poa x jemtlandica, X Pucciphippsia vacillans, and Trollius x apertus. Inclusions of such hybrids are argued for by a note.

Taxa assumed to have originated from some past hybridization process but reproductively isolated from their assumed parents, mostly by a ploidy difference (e.g., Anthoxanthum odoratum, Poa annua, and Saxifraga nathorstii), are treated as full species and not as hybrids, not least in view of the prevalent polyploidy in the arctic flora. The majority of arctic species have probably arisen in this way. The criterion is whether they have been stabilized and have attained a range of their own. There are some obvious borderline cases, especially in Poa and Potentilla, and the complications of agamic reproduction, this also especially in these two genera. Due to the vast differences among the cases, and among the opinions of the PAF collaborators, there is little consistency in this aspect in the Checklist. It should be improved in a future Panarctic Flora.

4  Casual taxa

Numerous taxa have been reported as adventives in the Arctic. Comparatively few of these are reported to be persistent (ca. 85 species and some races), and these are included in the main treatment below. The majority of adventive taxa have not been reported with persistent occurrences; they are casuals or most probably so. The main body of these are annuals or biennials, able to germinate in the Arctic but not to reach maturity and produce germinable seeds. The casuals range from those reported only once to those appearing fairly regularly in several settlements. We have mainly applied secondary sources in compiling this survey: for Greenland Porsild (1932), Pedersen (1972), and Böcher et al. (1978), for Iceland Kristinsson (2008), for Russia Sekretareva (1999, 2004), for Alaska Hultén (1968a), and circumpolarly Hultén and Fries (1986). For Canada and Norway (incl. Svalbard) the main collections have been consulted. Many additional adventives may have been documented from arctic localities in the collections or reported in works we have not consulted. The taxa are presented in alphabetic order.


Allium angulosum L. – European Russia: Malozemelskaya Tundra (Kobeleva 1976a), considered adventive there by Sekretareva (1999). Perennial. Status unknown but most probably casual.
Allium cepa L. – Russian Far East: East Chukotka (Sekretareva 1999, 2004). Perennial.


Amaranthus albus L. – Siberia: Taimyr (Sekretareva 1999). Annual.
Amaranthus retroflexus L. – European Russia: Vorkuta (probably); Siberia: Taimyr (Sekretareva 1999). Canada: Churchill in Manitoba (Hultén 1968a). Greenland: one find (Pedersen 1972). Annual.
Atriplex hortensis L. – Norway: Svalbard (Gustafsson 2001). Annual.
Atriplex patula L. – Greenland: a township weed with 2–3 finds (Pedersen 1972). Annual. For reports as native, see Excluded taxa.
Atriplex sagittata Borkh. (A. hortensis subsp. nitens (Schkuhr) Pons). – Norway: Svalbard (Liska and Soldán 2004). Annual.
Axyris amaranthoides L. – European Russia: Vorkuta (probably); Siberia: Dudinka (probably) in Taimyr; Russian Far East: West and East Chukotka (Sekretareva 1999, 2004). Canada: Churchill in Manitoba (Korobkov PAF proposal). Annual.
Chenopodium acerifolium Andrz. – Siberia: Dudinka in Taimyr (Sekretareva 1999). Annual.
Chenopodium berlandieri Moq. – Alaska: the Brooks Range; Canada: the Mackenzie River delta in NWT (Hultén 1968a). Annual. Status unknown but most probably casual.
Chenopodium ficifolium Sm. – Siberia: Taimyr (Sekretareva 1999). Annual.
Chenopodium glaucum L. – European Russia: Kanin–Pechora; Russian Far East: perhaps East or South Chukotka (Sekretareva 1999). Canada: Hudson Bay at the entrance to James Bay (Clemants and Mosyakin 2003). Greenland (Porsild 1932). Annual.
Chenopodium hybridum L. – Canada: Churchill in Manitoba (Scoggan 1978c). Annual.
Chenopodium leptophyllum (Moq.) B.D. Jacks. – Canada: Churchill in Manitoba (Hultén 1968a; Scoggan 1978c). Porsild and Cody (1980) did not map this species from the Arctic in Canada. Annual.
Chenopodium pratericola Rydb. – Canada: Churchill in Manitoba (Clemants and Mosyakin 2003). Annual.
Chenopodium rubrum L. subsp. humile (Hook.) Hultén (C. rubrum var. humile (Hook.) S. Watson). – Alaska: Nome on the Seward Peninsula (Clemants and Mosyakin 2003). Annual. Status unknown but almost certainly casual.
Chenopodium simplex (Torrey) Rafin. – Canada: the southwestern Hudson Bay in Manitoba (Clemants and Mosyakin 2003). Annual.
Chenopodium urbicum L. – Siberia: Taimyr; Russian Far East: East Chukotka (Sekretareva 1999, 2004). Annual.
Spinacia oleracea L. – Greenland (Porsild 1932). Annual.


Anethum graveolens L. – European Russia: Kanin–Pechora; Russian Far East: East Chukotka (Sekretareva 2004). Greenland (Pedersen 1972). Annual.


Anthemis arvensis L. – Greenland: one find (Porsild 1932). Annual.
Arctium tomentosum Mill. – European Russia: Kanin–Pechora (Sekretareva 1999). Greenland: one find (Porsild 1932). Perennial. May persist for a few years by vegetative growth but ultimately casual.
Artemisia absinthium L. – Norway: Svalbard (Liska and Soldán 2004). European Russia: Kanin–Pechora; Russian Far East: East Chukotka (Sekretareva 1999, 2004). Perennial.
Bellis perennis L. – Iceland: Siglufjördur (collected 2010, O), perhaps established. Norway: Vardø (Alm et al. 2003), probably casual. Perennial. A garden escape. Modern cultivars are not very hardy but old races persist and reproduce up to the treeline farther south in Scandinavia.
Bidens cernua L. – Alaska: the Seward Peninsula (Hultén 1968a; Hultén and Fries 1986). Annual. – A report from Canada: Churchill in Manitoba (Hultén and Fries 1986) may be a mistake for the native B. hyperborea.
Bidens tripartita L. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual.
Centaurea cyanus L. – Reported from arctic Russia by Sokolova (1987c), by Sekretareva (1999) specified as European Russia: the Murman area (probably not arctic, see Orlova 1966), Kanin–Pechora, and Polar Ural; and Siberia: Taimyr. Greenland: one find (Porsild 1932). Annual.
Centaurea jacea L. – European Russia: the Murman area (probably not arctic), Kanin–Pechora, and Polar Ural (Sekretareva 1999). Greenland: one find (Porsild 1932). Perennial. Perhaps persisting for some years but ultimately casual.
Centaurea phrygia L. – Reported from arctic Russia by Sokolova (1987c). Sekretareva (1999) reported only European Russia: the Murman area and there perhaps not arctic (Orlova 1966 mapped it only from the boreal Nikel area in the Pasvik valley). Perennial. Several clones of this species have persisted from the Second World War until today in the non-arctic Pasvik valley in northeastern Norway and the Murman area (see summary by Fremstad 2009).
Centaurea scabiosa L. – Reported from arctic Russia by Sokolova (1987c). Sekretareva (1999) reported only European Russia: the Murman area and there perhaps not arctic. Perennial. May persist for some years but probably not reproducing or persisting vegetatively.
Cota tinctoria (L.) J. Gay (Anthemis tinctoria L.) – European Russia: Liinahamari in the Murman area, in the Borderline Arctic (Orlova 1966). Biennial to perennial.
Galinsoga quadriradiata Ruiz & Pav. (G. ciliata (Raf.) S.F. Blake). – Greenland: one find (Pedersen 1972). Annual.
Helianthus annuus L. – Norway: Finnmark (several reports) and Svalbard (Liska and Soldán 2004). Russian Far East: East Chukotka (Sekretareva 1999, 2004). Greenland: one find (Pedersen 1972). Probably fairly frequent as seedlings in arctic settlements. Annual.
Lapsana communis L. – Iceland: Siglufjördur (AMNH). Norway: Vadsø (Elven et al. 2005). European Russia: the Murman area (perhaps not arctic there) and Kanin–Pechora (Sekretareva 1999). Greenland: two finds (Porsild 1932; Pedersen 1972). Annual.
Leontodon hispidus L. – European Russia: Kanin–Pechora (Sekretareva 1999). Perennial. Korobkov (PAF proposal) indicated it as persistent but not yet documented as such from arctic localities. A persistent ruderal in non-arctic parts of the northwesternmost Murman area.
Matricaria chamomilla L. – Norway: Måsøy (near arctic), persisting for at least some years (Elven et al. 2005). European Russia: the Murman and the Vorkuta areas, persistence unknown (Sekretareva 2004). Greenland: frequent in settlements (Pedersen 1972). Annual.
Senecio erucifolius L. – Siberia: Taimyr (Sekretareva 1999). Perennial.
Sonchus asper (L.) Hill. – European Russia: the Murman area (perhaps not arctic) and Kanin–Pechora (Sekretareva 1999). Greenland: one find (Porsild 1932). Annual
Sonchus oleraceus L. – European Russia: the Murman area (perhaps not arctic) and Kanin–Pechora (Sekretareva 1999). Greenland: one find (Porsild 1932). Annual.
Tragopogon pratensis L. – European Russia: Kanin–Pechora (Sekretareva 1999), both subsp. pratensis and subsp. orientalis (L.) Celak. (T. orientalis L.). Perennial.
Xanthium strumarium L. – Greenland: one find (Porsild 1932). Annual.


Amsinckia menziesii (Lehm.) A. Nelson & J.F. Macbr. – Alaska: Nome on the Seward Peninsula (Hultén 1968a). Annual.
Anchusa arvensis (L.) M. Bieb. (Lycopsis arvensis L.). – Norway: Vardø (Elven et al. 2005). Greenland: two finds (Porsild 1932; Pedersen 1972). Annual.
Buglossoides arvensis (L.) I.M. Johnst. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual.
Lappula marginata (M. Bieb.) Gürke. – Iceland: Siglufjördur (AMNH). Annual.


Arabidopsis thaliana (L.) Heynh. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual. Status unknown but probably casual.
Arabis hirsuta (L.) Scop. s. lat. – Greenland: a casual reported as A. hirsuta var. glaberrima Wahlenb. but suggested to be another, North American glabrous variety (Pedersen 1972), and then of A. pycnocarpa rather than A. hirsuta s. str.
Berteroa incana (L.) DC. – Jalas et al. (1996) mapped this species as persistent in the Bolshezemelskaya Tundra and Polar Ural in European Russia. We find persistency of this perennial species in the Arctic improbable.
Brassica juncea (L.) Czern. – European Russia: Kanin–Pechora; Siberia: Taimyr (Sekretareva 1999). Greenland: one find (Pedersen 1972). Annual.
Brassica napus L. – Greenland: at least seven finds (Porsild 1932; Pedersen 1972). Annual to biennial.
Brassica oleracea L. – Russian Far East: East Chukotka (Sekretareva 1999, 2004, with doubts). Greenland (Porsild 1932, with doubts). Mostly biennial.
Bunias orientalis L. – Jalas and Suominen (1994) mapped this species as persistent in Polar Ural (probably Vorkuta) in European Russia. Sekretareva (1999) in addition reported Siberia: Dudinka (probably) in Taimyr. Mostly biennial. Fairly thermophilous and improbable as persistent in the Arctic.
Camelina sativa (L.) Crantz. – Norway: Vardø (Elven et al. 2005). Siberia: Taimyr (Sekretareva 1999). Greenland: one find (Pedersen 1972). Annual.
Cardamine hirsuta L. – Iceland: Siglufjördur (2010, O). Annual, probably introduced with nursery plants. Most probably casual.
Catolobus pendulus (L.) Al-Shehbaz (Arabis pendula L.). – Siberia: Taimyr; Russian Far East: East Chukotka (Sekretareva 2004). Biennial.
Chorispora tenella (Pall.) DC. – European Russia: Kanin–Pechora; Russian Far East: East Chukotka (Sekretareva 2004). Annual.
Conringia orientalis (L.) Dumort. – Norway: Svalbard 1928 (Elven et al. 2005). European Russia: Kanin–Pechora (Sekretareva 1999). Greenland: one find (Porsild 1932). Annual.
Erysimum cheiranthoides L. s. str. – Norway: Svalbard (several reports). Greenland: one find (Pedersen 1972). Annual. – Other literary records are unreliable due to confusion with E. altum (see main text).
Erysimum repandum L. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual.
Isatis tinctoria L. subsp. tinctoria. – Jalas and Suominen (1994) mapped this race as persistent in Polar Ural in European Russia. Biennial. Status unknown but probably casual.
Leavenworthia torulosa A. Gray. – Reported from European Russia: the lower Pechora River area 1912 and 1915, see Kotov (1975). Mapped by Jalas and Suominen (1994: map 2378) as (possibly) persistent. Not included by Sekretareva (1999, 2004), which might mean that the material has been re-identified as something else. The record of this North American plant from one site in northern European Russia is strange and not confirmed by more recent Russian sources.
Lepidium densiflorum Schrad. – Norway: Svalbard (Liska and Soldán 2004). Canada: Churchill in Manitoba (Hultén 1968a). Greenland: one find (Pedersen 1972). Annual.
Lepidium heterophyllum Benth. – Iceland: Siglufjördur (AMNH). Perennial but probably not established.
Lepidium ramosissimum A. Nelson (L. bourgeauanum Thell.). – Canada: Churchill in Manitoba (Porsild and Cody 1980). Annual. This species is persistent far north both in Alaska and in Canada but is probably casual in the Arctic.
Lepidium ruderale L. – European Russia: Kanin–Pechora and Polar Ural; Siberia: Taimyr (Sekretareva 1999). Annual.
Lepidium sativum L. – Iceland: one locality (Kristinsson 2008). Russian Far East: East Chukotka (Sekretareva 2004). Greenland: several finds (Porsild 1932), stated by Böcher et al. (1978) as "naturaliseret" (naturalized) which seems improbable. Annual.
Neslia paniculata (L.) Desv. – European Russia: Kanin–Pechora and Novaya Zemlya; Siberia: Taimyr; Russian Far East: East Chukotka? (Sekretareva 1999, 2004). Canada: Churchill in Manitoba (Hultén 1968a). Annual.
Noccaea caerulescens (J. Presl & C. Presl) F.K. Mey. (Thlaspi caerulescens J. Presl & C. Presl). – Norway: Svalbard? (an unsubstantiated report). Perennial. – Noccaea caerulescens is a central European species introduced to northern Europe before the 1870s. It is very hardy, fully established, and reproduces by seed in the Scandinavian mountains up to above 1200 m, 200–300 m above the treeline, at present spreading northwards at least in Fennoscandia and approaching the Arctic. Persistent arctic occurrences are soon to be expected.
Raphanus raphanistrum L. – Iceland and Norway: reported by numerous sources from several arctic localities. European Russia: Kanin–Pechora and Novaya Zemlya; Siberia: Taimyr (Sekretareva 1999). Greenland: several finds (Porsild 1932; Pedersen 1972). Annual.
Raphanus sativus L. – Russian Far East: East Chukotka? (Sekretareva 1999, 2004). Greenland: one find (Porsild 1932). Biennial.
Sinapis alba L. – European Russia: Kanin–Pechora; Siberia: Taimyr (Sekretareva 1999). Greenland: two finds (Porsild 1932; Pedersen 1972). Annual.
Sinapis arvensis L. – Iceland: several finds reported. Norway: Finnmark and Svalbard, several finds reported. European Russia: the Murman area and Kanin–Pechora; Siberia: Taimyr and the Lena River area; Russian Far East: East Chukotka (Sekretareva 1999). Alaska: several finds reported. Greenland: numerous finds (Porsild 1932; Pedersen 1972). Annual.
Sisymbrium altissimum L. – European Russia: Kanin–Pechora; Siberia: Taimyr (Sekretareva 1999). Canada: Churchill in Manitoba (Hultén 1968a). Greenland: three finds but reported to expand in Julianehåb in 1946 (Pedersen 1972). Annual. We find persistence in Greenland improbable.
Sisymbrium loeselii L. – European Russia: Kanin–Pechora; Russian Far East: East Chukotka (Sekretareva 1999, 2004). Reported also from Canada. Annual.
Sisymbrium polymorphum (Murray) Roth. – European Russia: uncertain report from Kanin–Pechora (Sekretareva 1999). Perennial. Status unknown but probably casual. This is an eastern European and Siberian 'steppe' species that reaches far north as native, e.g., along the Lena River.
Turritis glabra L. (Arabis glabra (L.) Bernh.). – Sekretareva (1999) reported the species as native and to reach the Arctic in European Russia on the Murman coast, but she seems to have included parts of that region in the Arctic that we want to exclude (e.g., the Ponoj area). Jalas and Suominen (1994) did not consider the species persistent in arctic Europe. Canada: one Hudson Bay locality (Hultén and Fries 1986) but probably not persistent there either. Biennial.


Campanula patula L. – European Russia: the Murman area (perhaps not in the Arctic) and Kanin–Pechora (Sekretareva 1999). Biennial.


Cannabis sativa L. – European Russia: Kanin–Pechora (Sekretareva 1999). Greenland: five finds (Porsild 1932). Annual.


Agrostemma githago L. – Norway: Vardø and Svalbard (Elven et al. 2005). European Russia: the Murman area (perhaps not in the Arctic) and Kanin–Pechora (Sekretareva 1999). Annual.
Cerastium glomeratum Thuill. – Alaska: the Brooks Range (Hultén 1968a). Some other reports as a greenhouse weed, e.g., in Greenland (Pedersen 1972). Annual.
Lychnis flos-cuculi L. (Silene flos-cuculi (L.) Clairv., Coronaria flos-cuculi (L.) A. Braun). – European Russia: the Murman area, Kanin–Pechora, and Polar Ural (Sekretareva 1999). Perennial. Status unknown, occurrence(s) must be confirmed as persistent before inclusion in the main text.
Silene brachypetala (Hornem.) Fenzl. – Russian Far East: East Chukotka (e.g., Sekretareva 1999), not documented as persistent there according to Petrovsky (comment). Perennial.
Silene latifolia Poir. subsp. alba (Mill.) Greuter & Burdet. – European Russia: the Murman area, Kanin–Pechora, and Polar Ural; Siberia: Taimyr; Russian Far East: East Chukotka (Sekretareva 1999). Canada: several reports from arctic localities. Greenland: two finds (Porsild 1932). Mainly annual.
Silene noctiflora L. – Reported by several sources from arctic localities in Russia. Alaska: Nome on the Seward Peninsula (Hultén 1968a). Canada: Churchill in Manitoba (Hultén 1968a). Greenland (Pedersen 1972). Annual.
Spergula arvensis L. – Iceland (Kristinsson 2008, 2010). Norway (Elven et al. 2005). European Russia: the Murman area and Kanin–Pechora (Sekretareva 1999). Alaska: the Yukon River Delta (Hultén 1968a). Greenland (Porsild 1932; Pedersen 1972). Annual. Status unknown; we have no documentation yet that this species persists anywhere in the Arctic.
Vaccaria hispanica (Mill.) Rauschert. – Canada: Churchill in Manitoba (Hultén and Fries 1986). Annual.


Convolvulus arvensis L. – European Russia: Kanin–Pechora (Sekretareva 1999). Greenland: one find (Pedersen 1972). Perennial.


Carex leporina L. – European Russia: two localities on Kildin Island and east of Teriberka in the Murman area (Kuzeneva 1954). Perennial. Not confirmed to persist and not included by Sekretareva (1999, 2004). Casual finds have been made in several places in northern Fennoscandia (outside the Arctic).


Euphorbia helioscopia L. – Collected at a few places in the Arctic, e.g. in Norway: Vardø (Elven et al. 2005). Annual.


Astragalus danicus Retz. – European Russia: Kanin–Pechora (Sekretareva 1999). Perennial.
Lupinus sp. – Greenland: one find of an unidentified species (Porsild 1932). The most frequent garden plant is L. polyphyllus Lindl. Perennial.
Medicago arabica (L.) Huds. – Greenland: one find (Pedersen 1972). Annual.
Medicago falcata L. (M. sativa L. subsp. falcata (L.) Arcang.). – European Russia: the Murman area (perhaps not in the Arctic) and Kanin–Pechora; Siberia: the Lena River area (Sekretareva 1999). Biennial to perennial.
Medicago lupulina L. – Norway: Vadsø and Svalbard (Elven et al. 2005). European Russia: Kanin–Pechora and Novaya Zemlya; Siberia: the Lena River area; Russian Far East: East Chukotka (Sekretareva 1999). Alaska: Nome on the Seward Peninsula (Hultén 1968a). Greenland: about ten finds (Porsild 1932; Pedersen 1972). Annual.
Medicago polymorpha L. – Norway: Svalbard (Elven et al. 2005). Annual.
Medicago sativa L. (M. sativa L. subsp. sativa). – Russian Far East: East Chukotka (Sekretareva 1999). Canada: Churchill in Manitoba (Hultén 1968a). Biennial to perennial.
Melilotoides platycarpos (L.) Soják (Trigonella platycarpos L.). – Russian Far East: East Chukotka (Sekretareva 1999, 2004). Annual.
Melilotus altissimus Thuill. – Greenland: three finds (Pedersen 1972). Annual.
Melilotus indicus (L.) All. – Greenland: one find (Pedersen 1972). Annual.
Melilotus officinalis (L.) Lam. – Norway: Vadsø (Elven et al. 2005). European Russia: Kanin–Pechora (Sekretareva 1999). Canada: Churchill in Manitoba (Hultén 1968a). Annual.
Melilotus suaveolens Ledeb. – Russian Far East: West and South Chukotka (Sekretareva 1999). Annual. Status unknown but most probably casual.
Pisum sativum L. s. lat. – Collected in many arctic localities, e.g.: in Norway: Båtsfjord, Jan Mayen, Bear Island, and in Spitsbergen and other Svalbard islands (see Elven et al. 2005); European Russia: Kanin–Pechora (Sekretareva 1999); and Greenland (Porsild 1932; Pedersen 1972; Böcher et al. 1978). Annual.
Trifolium arvense L. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual.
Trifolium aureum Pollich (Chrysaspis aurea (Pollich) Greene). – Greenland: one find (Pedersen 1972). Biennial.
Trifolium cyathiferum Lindl. – Russian Far East: near Anadyr town in South Chukotka in 1909. Annual.
Trifolium spadiceum L. (Chrysaspis spadicea (L.) B.D. Greene). – European Russia: the Murman area, Kanin–Pechora, and Polar Ural (Sekretareva 1999). Annual.
Trifolium variegatum Nutt. – Alaska: the Norton Sound area (Hultén 1968a). Annual.
Vicia hirsuta (L.) Gray. – Norway: Vardø (Elven et al. 2005). European Russia: Kanin–Pechora and Polar Ural (Sekretareva 1999). Greenland: one find (Porsild 1932). Annual.
Vicia sativa L. subsp. nigra (L.) Ehrh. (V. angustifolia L.). – European Russia: Kanin–Pechora (Sekretareva 1999). Greenland: one find (Porsild 1932). Annual.
Vicia sativa L. subsp. sativa. – Norway: Svalbard (Elven et al. 2005). European Russia: Kanin–Pechora (Sekretareva 1999). Greenland: ca. 5 finds (Porsild 1932; Pedersen 1972). Annual.
Vicia tenuifolia Roth. – European Russia: Kanin–Pechora (Sekretareva 1999). Perennial.


Fumaria officinalis L. – Norway: Nordkapp (Elven et al. 2005). European Russia: Kanin–Pechora (Sekretareva 1999). Greenland: one find (Porsild 1932). Annual.


Erodium cicutarium (L.) L'Hér. ex Aiton. – Norway: Svalbard (Elven et al. 2005). European Russia: the Murman area (perhaps not in the Arctic), Kanin–Pechora, and Novaya Zemlya; Siberia: Taimyr (Sekretareva 1999). Greenland: two finds (Porsild 1932; Pedersen 1972). Annual.
Erodium stephanianum Willd. – Russian Far East: East Chukotka (Sekretareva 1999, 2004). Tzrenova (1988) did not map this species from Chukotka. Annual.
Geranium bicknellii Britton. – Canada: the Churchill area in Manitoba (Porsild and Cody 1986) but Scoggan (1978c) only reported it from well south of Churchill and from the James Bay area. Annual or biennial. Status unknown but probably casual.
Geranium molle L. – Greenland: one find (Pedersen 1972). Annual.
Geranium pusillum L. – Greenland: one find (Pedersen 1972). Annual.
Geranium soboliferum Kom. – Russian Far East: East Chukotka (Sekretareva 1999, 2004). Tzrenova (1988) did not map this species from Chukotka or nearby areas. Perennial?
Geranium vlassovianum Fisch. ex Link. – Russian Far East: East Chukotka (Sekretareva 1999, 2004). Tzrenova (1988) did not map this species from Chukotka or nearby areas. Perennial.


Ribes dikuscha Fisch. ex Turcz. – Russian Far East: East Chukotka. Perennial. Gladkova (PAF proposal) reported it as "introduced, occasionally" in East Chukotka. It is uncertain whether it is persistent there.


Dracocephalum thymiflorum L. – European Russia: the Murman area (perhaps not in the Arctic) and Kanin–Pechora (Sekretareva 1999). Siberia: Vasilek in Taimyr (Peschkova 1997). Annual.
Galeopsis ladanum L. – European Russia: the Murman area (perhaps not in the Arctic), Kanin–Pechora, and Polar Ural (Sekretareva 1999). Annual.
Galeopsis speciosa Mill. – Norway: Vardø (Alm et al. 2003). European Russia: the Murman area (perhaps not in the Arctic) and Kanin–Pechora (Sekretareva 1999). Annual.
Lamium amplexicaule L. – Greenland: several finds in three localities, "seemingly acclimatized" (Pedersen 1972). Annual. Improbable to persist in Greenland in spite of Pedersen's note.
Lamium confertum Fr. (L. moluccellifolium auct.). – Greenland: one find (Pedersen 1972). Annual.
Lamium hybridum Vill. – European Russia: the Murman area but probably not in the Arctic (Sekretareva 1999). Greenland: one find in Ivigtut but stated as "has doubtlessly long existed in this place" (Lagerkranz, cited by Pedersen 1972). Annual. Improbable to persist in Greenland in spite of Pedersen's note.
Leonurus glaucescens Bunge. – Russian Far East: East Chukotka (Sekretareva 1999, 2004). Krestovskaya (1995) did not include this species from the Russian Far East. Perennial.
Stachys palustris L. subsp. palustris. – European Russia: the Murman area (perhaps not in the Arctic) and Kanin–Pechora (Sekretareva 1999). Perennial and strongly rhizomatous; may persist for a long time.


Linum usitatissimum L. – European Russia: Kanin–Pechora; Siberia: the Lena River area (Sekretareva 1999). Annual.


Malva neglecta Wallr. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual.
Malva pusilla Sm. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual.


Anagallis arvensis L. – European Russia: Kanin–Pechora (Sekretareva 1999). Greenland: two finds (Porsild 1932; Pedersen 1972). Annual.


Oenothera biennis L. s. lat. – Canada: Churchill in Manitoba (Hultén and Fries 1986: map 1354). Biennial.


Pedicularis resupinata L. – Russian Far East: Anadyr town in South Chukotka, reported by Ivanina (PAF proposal) as adventive. Also reported by Sekretareva (1999) from Chukotka as adventive. Perennial. There is no information about stability.
Rhinanthus angustifolius C.C. Gmel. (incl. R. vernalis (N. Zing.) Schischk. & Serg.). – European Russia: Kanin–Pechora and Polar Ural (Sekretareva 1999). Annual. Status unknown but probably casual.


Oxalis corniculata L. – Greenland: one find (Porsild 1932). A frequent weed in greenhouses and among potted plants but not surviving the arctic climate outdoors for many days. Annual.


Chelidonium majus L. – Greenland: one find (Porsild 1932). Perennial. Polunin (1956) reported it as persistent in Greenland, possibly because Porsild found it flowering and with developing fruits. We consider stability improbable.
Papaver dubium L. – Greenland: one find (Porsild 1932). Annual.
Papaver somniferum L. – European Russia: Kanin–Pechora (Sekretareva 1999). Greenland: four finds (Pedersen 1972). Annual.


Chaenorhinum minus (L.) Lange. – Canada: Churchill in Manitoba (Hultén and Fries 1986). Annual.
Plantago coronopus L. – Greenland: one find (Porsild 1932). Annual.
Veronica arvensis L. – Greenland: two finds (Porsild 1932; Pedersen 1972). Annual.
Veronica gentianoides Vahl. – Iceland: Olafsfjördur (AHMN). Norway: Nordkapp, an escaped garden ornamental in a swamp (TROM). Perennial, rhizomatous, and may persist due to vegetative growth but not documented to reproduce. If the plant is confirmed to persist and spread by vegetative means in Olafsfjördur or Nordkapp, it should be accepted as an arctic species according to our criteria.
Veronica peregrina L. subsp. xalapensis (Humb., Bonpl. & Kunth) Pennell. – Canada: north to York Factory on the southwestern Hudson Bay but maybe outside the Arctic (Porsild and Cody 1980; Scoggan 1979). Annual.
Veronica persica Poir. – Greenland: two finds (Pedersen 1972). Annual.


Anisantha tectorum (L.) Nevski (Bromus tectorum L.). – Alaska: Nome on the Seward Peninsula (Hultén 1968a). Greenland: one find (Porsild 1932). Annual.
Apera spica-venti (L.) P. Beauv. – Norway: Vardø 1858 (O). European Russia: the Murman area (probably not in the Arctic) and Kanin–Pechora (Sekretareva 1999). Annual.
Avena fatua L. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual.
Avena sativa L. – Many reports from Norway incl. Svalbard (Elven et al. 2005), European Russia and the Russian Far East (Sekretareva 1999), and Greenland (Porsild 1932; Pedersen 1972), Annual.
Beckmannia eruciformis (L.) Host subsp. eruciformis. – European Russia: the Murman area but perhaps not in the Arctic (Sekretareva 1999). Perennial. For B. eruciformis subsp. borealis in the Vorkuta area, see the main text.
Bromus arvensis L. – European Russia: the Murman area (probably not in the Arctic) and Kanin–Pechora (Sekretareva 1999). Annual.
Bromus hordeaceus L. – Alaska: Nome on the Seward Peninsula (Hultén 1968a). Greenland: at least five finds (Porsild 1932; Pedersen 1972). Annual.
Bromus secalinus L. – European Russia: the Murman area (probably not in the Arctic) and Kanin–Pechora (Sekretareva 1999). Alaska: Nome on the Seward Peninsula and in the Yukon River Delta (Hultén 1968a). Annual.
Ceratochloa marginata (Nees ex Steud.) B.D. Jacks. (Bromus marginatus Nees ex Steud.). – Alaska: Nome on the Seward Peninsula (Hultén 1968a). Annual.
Deschampsia danthonioides (Trin.) Munro. – Alaska: Nome on the Seward Peninsula (Hultén 1968a). Annual.
Deschampsia elongata (Hook.) Munro. – Alaska: Nome on the Seward Peninsula (Hultén 1968a). Perennial.
Echinochloa crus-galli (L.) P. Beauv. – Russian Far East: East Chukotka (Sekretareva 1999, 2004). Annual.
Festuca trachyphylla (Hack.) Krajina. – Canada: adventive and possibly persisting in Quebec north to 54N (Aiken in comment) but does not seem to reach the Arctic. May have been introduced as a cover plant in some settlements. Perennial.
Hordeum distichon L. – Greenland: three finds (Porsild 1932; Pedersen 1972). Annual.
Hordeum vulgare L. – Norway: Vadsø and Svalbard (Elven et al. 2005). Russian Far East: perhaps East Chukotka (Sekretareva 1999). Greenland: at least six finds (Porsild 1932; Pedersen 1972). Annual.
Lolium multiflorum Lam. – Norway: Finnmark (Jalas 1991). Alaska: Nome on the Seward Peninsula (Hultén 1968a). Greenland: four finds (Porsild 1932; Pedersen 1972). Annual to perennial. In Greenland in attempted lawns and brought with hay from Denmark, most probably not persisting
Lolium temulentum L. – Alaska: the Norton Sound area (Hultén 1968a). Greenland (Pedersen 1972). Annual.
Panicum miliaceum L. – Greenland (Pedersen 1972). Annual.
Phalaris canariensis L. – Norway: Nordkapp (Elven et al. 2005). Greenland (Pedersen 1972). Annual.
Poa compressa L. – European Russia: the Murman area (Kuzeneva 1953). Russian Far East: East Chukotka (Sekretareva 1999). Also reported from the Arctic in Alaska and Canada. Perennial. Status unknown but most probably casual.
Poa remota Forselles. – European Russia: Kanin–Pechora (Sekretareva 1999). Perennial. Status unknown but assumed casual. Otherwise, this species is not ruderal.
Polypogon monspeliensis (L.) Desf. – Alaska: Nome on the Seward Peninsula (Hultén 1968a). Annual.
Schedonorus arundinaceus (Schreb.) Dumort. (S. phoenix (Scop.) Holub, Festuca arundinacea Schreb.). – Alaska: Nome on the Seward Peninsula (Hultén 1968a). Perennial. This species is often cultivated as fodder or as a lawn grass. The report is probably based on escaped and/or ruderal plants. Fairly frequent visits to Nome 1998–2005 have not resulted in new finds, and we assume the species to be casual in the Arctic.
Secale cereale L. – Norway: Svalbard (see Porsild 1932). European Russia: Kanin–Pechora; Russian Far East: perhaps East Chukotka (Sekretareva 1999). Greenland: many finds (Porsild 1932; Pedersen 1972). Annual.
Triticum aestivum L. – European Russia: Kanin–Pechora (Sekretareva 1999). Greenland (Porsild 1932; Pedersen 1972). Annual.
Triticum durum Desf. – Russian Far East: Chukotka (Sekretareva 1999). Annual.


Collomia linearis Nutt. – Approaches the Arctic both in Alaska (Hultén 1968a) and in Canada: Churchill in Manitoba (Porsild and Cody 1980). Murray and Elven found no documentation of persistence in the Arctic in Alaska. Annual.


Fagopyrum esculentum Moench. – European Russia: Kanin–Pechora; Russian Far East: East Chukotka (Sekretareva 1999, 2004). Annual.
Fagopyrum tataricum (L.) Gaertn. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual.
Fallopia convolvulus (L.) Á. Löve (Polygonum convolvulus L.). – Iceland (Kristinsson 2008). Norway incl. Svalbard (Elven et al. 2005). European Russia: the Murman area (perhaps not in the Arctic), Kanin–Pechora, and Novaya Zemlya; Siberia: Taimyr and the Lena River area; Russian Far East: West and East Chukotka (Sekretareva 1999, 2004). Alaska: the Yukon River Delta (Hultén 1968a). Canada: Hudson Bay (Hultén 1968a). Greenland: more than 15 finds (Porsild 1932; Pedersen 1972). Annual. This species is a frequent adventive in the Arctic but persists nowhere.
Persicaria lapathifolia (L.) Gray, including subsp. pallida (With.) S. Ekman & T. Knutsson (Polygonum lapathifolium L.). – Norway: Vadsø and Vardø (O, TROM). European Russia: the Murman area (perhaps not in the Arctic) and Kanin–Pechora; Siberia: Taimyr; Russian Far East: West and East Chukotka (Sekretareva 1999, 2004). Greenland: several finds (Porsild 1932; Pedersen 1972). The weedy plant is usually subsp. pallida, whereas subsp. lapathifolia mainly is a temperate to southern boreal shore and swamp plant. Annual.
Persicaria maculosa Gray (Polygonum persicaria L.). – European Russia: Kanin–Pechora; Russian Far East: East Chukotka (Sekretareva 1999, 2004). Greenland: several finds (Porsild 1932; Pedersen 1972). Annual.
Rheum x hybridum J.A. Murray. – Norway: Vardø, two localities, only persisting from garden refuse without any spread (Alm et al. 2003). Perennial.
Rumex obtusifolius L. – Greenland: one find (Porsild 1932). Perennial.
Rumex ucranicus Besser ex Spreng. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual.


Primula veris L. – Norway: Vadsø, an escaped garden ornamental, probably not persisting at the locality (Elven et al. 2005). Perennial.


Consolida regalis Gray. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual.
Myosurus minimus L. – Jalas and Suominen (1989) mapped this species to persist in one Atlas florae europaeae square in the Arctic in the eastern Bolshezemelskaya Tundra in European Russia. Martinenko (1976b) gave the locality as Vorkuta. It has been included and mapped from there, as persistent, in later Russian floras but was excluded by Sekretareva (1999). It is unlikely that this annual, thermophilous species persists anywhere in the Arctic.
Ranunculus acris L. subsp. friesianus (Jordan) Syme. – Norway: Svalbard (Liska and Soldán 2004). Perennial. Reported to flower and perhaps to persist, but most probably casual.


Reseda lutea L. – European Russia: Kanin–Pechora (Sekretareva 1999). Biennial to perennial.


Geum aleppicum Jacq. subsp. aleppicum. – Russian Far East: East Chukotka (Sekretareva 1999). Yakubov and Nedolushko (1996) mapped a locality near Provideniya. Perennial. Status unknown but probably casual.
Geum macrophyllum Willd. subsp. macrophyllum. – Russian Far East: Chukotka (Sekretareva 1999). Yakubov and Nedolushko (1996) did not map localities in Chukotka. Perennial. Status unknown but probably casual.
Malus baccata (L.) Borkh. – Russian Far East: East Chukotka (Sekretareva 1999, 2004). Yakubov and Nedolushko (1996) did not map localities in Chukotka. Perennial.
Malus x domestica Borkh. – Norway: Svalbard (Liska and Soldán 2004, also many previous reports). Seedlings are certainly frequent but overlooked in many other arctic settlements. Perennial.
Malus sylvestris (L.) Mill. – Russian Far East: East Chukotka (Sekretareva 1999). Perennial.
Potentilla intermedia L. – Norway: Nordkapp (Elven et al. 2005). European Russia: Kanin–Pechora (Sekretareva 2004). Biennial.
Potentilla neglecta Baumg. (Potentilla impolita auct.). – Norway: Nordkapp (e.g., Elven et al. 2005). European Russia: the Murman and the Vorkuta areas (Sekretareva 2004). Perennial. Status unknown but probably casual.
Potentilla supina L. s. lat. – Russian Far East: East Chukotka (Sekretareva 1999). Yakubov and Nedolushko (1996) did not map localities in Chukotka. Annual.
Potentilla thuringiaca Bernh. ex Link. – European Russia: the Murman area (Sekretareva 1999). Perennial. Status unknown but probably casual.
Prunus cf. domestica L. – Norway: Svea in Svalbard, seedlings in 2009 (UNIS herbarium). Perennial.
Sibbaldianthe bifurca Juz. (Potentilla bifurca L.) s. lat. – Siberia: Taimyr; Russian Far East: East Chukotka (Sekretareva 1999). Perennial. Status unknown but probably casual.


Galium spurium L. subsp. vaillantii (DC.) Gaudin. – Norway: Finnmark (Elven et al. 2005). Siberia: Taimyr; Russian Far East: East Chukotka (Sekretareva 1999). Annual. Status unknown but probably casual.


Verbascum thapsus L. – Greenland: one find (Pedersen 1972). Biennial.


Datura stramonium L. – European Russia: Kanin–Pechora (Sekretareva 1999). Annual.
Hyoscyamus niger L. – European Russia: Kanin–Pechora (Sekretareva 1999). Biennial.
Lycopersicon esculentum Mill. (Solanum lycopersicum L.). – Norway: Vadsø (Elven et al. 2005). European Russia: Kanin–Pechora; Russian Far East: East Chukotka (Sekretareva 1999). Annual.
Solanum tuberosum L. – The potato has been found repeatedly in many arctic settlements, e.g., in Russia in Kanin, the Vorkuta area, and East Chukotka (Sekretareva 2004) but certainly not persisting anywhere. Perennial.


Viola arvensis Murray. – European Russia: Kanin–Pechora (Sekretareva 1999). Greenland: three finds (Porsild 1932; Pedersen 1972). Annual. Tzvelev (in comment) prefers to keep V. arvensis in the main text as we can not be sure whether it persists or not in the Vorkuta area. We assume it to be casual.
Viola x wittrockiana Gams ex Kappert. – Norway: Vardø, garden escape (Alm et al. 2003). Normally an annual in northern sites.

5  Excluded taxa

The following species and races have been reported from the Arctic or at near arctic localities but we exclude them from the Checklist. The five main reasons for exclusion are: (1) the records are from areas outside the Arctic as circumscribed for the Checklist (i.e., not even "borderline"); (2) the records are based on misidentifications (when it concerns single or a few specimens); (3) we understand or circumscribe the taxon differently from many previous authors; (4) the taxon has been misunderstood and its name has been misapplied (when it concerns whole parts of ranges); or (5) we do not accept a taxon. Comments are by Elven unless otherwise stated.


Atriplex patula L. – Misidentified. – Atriplex patula is recorded as casual in Greenland (see Casual taxa). The very numerous reports of this species as a native seashore plant reaching the Arctic are erroneous (e.g., Rebristaya 1966 from the Rybachi Peninsula in the Murman area, Jalas and Suominen 1980 from large parts of northern Europe, and some later authors). All checked records belong to other species, mainly A. glabriuscula or A. longipes subsp. praecox. The northernmost localities with stable occurrences of A. patula recognized today in northwestern Europe are found in Norway in the boreonemoral zone near Trondheim at about 64N.


Angelica lucida L. – Name applied differently. – This name has been widely applied to a northwestern North American plant (e.g., Hultén 1968a; Cody 1996). We restrict the name A. lucida to a non-arctic, eastern North American plant and apply the name A. gmelinii to the amphi-Pacific and amphi-Beringian plant.
Conioselinum chinense (L.) Britton, Sterns & Poggenb. – Name misapplied. – In spite of "chinense", this species is described with type from New York and its name is inapplicable for the Pacific plant to which it often has been applied. We recognize the Pacific plant as C. pacificum.
Phoiodicarpus sibiricus (Fisch. ex Spreng.) Koso-Pol. – Not arctic. – Tikhomirov (1980) reported P. sibiricus from the lower Lena River area in Siberia. Yurtsev (in comment) stated it not to reach the Arctic.


Apocynum androsaemifolium L. – Not arctic. – This species approaches the Arctic in the northern Yukon Territory (Cody 2000) and in Manitoba at Hudson Bay (Scoggan 1979: Gillam south of Churchill and York Factory) but does not seem to approach closely enough to reach the Borderline Arctic.


Achillea alpina L. subsp. sibirica (Ledeb.) (Achillea sibirica Ledeb.). – Name misapplied. – The northwestern North American plant to which the name A. sibirica has been applied (e.g., Hultén 1968a; Porsild and Cody 1980; Cody 1996) belong to subsp. multiflora (A. multiflora) and not to the non-arctic Asian subsp. sibirica (A. sibirica).
Antennaria dioiciformis Kom. – Misidentified. – The distinctive A. dioiciformis was described from Kamtchatka. Petrovsky (1987c) mapped it with a fairly wide range in the Russian Far East, especially frequent along the arctic Bering Strait. All specimens from arctic Chukotka (in LE, inspected by Petrovsky and Elven) belong to A. friesiana. Only females are found among the collected specimens, indicating that this is a polyploid apomict (probably subsp. friesiana). The chromosome vouchers from Chukotka assigned to A. dioiciformis were also all misidentified. They belong to A. friesiana and A. monocephala.
Antennaria lanata (Hook.) Greene. – Name misapplied. – This name has sometimes been applied, especially by Russian authors, to the northwestern North American plant of the A. carpatica group. The relevant plant is A. pulchella, whereas A. lanata is a more southern Cordilleran species.
Artemisia campestris L. – Name misapplied. – Many North American authors assign the narrow-leaved species A. borealis and A. canadensis under this European name. The name refers to a temperate, central and northern European plant that does not approach the Arctic anywhere.
Artemisia laciniata Willd. – Name misapplied. – The northern material assigned to A. laciniata (e.g., Hultén 1968a) belongs to A. tanacetifolia.
Artemisia laciniatiformis Kom. – Name misapplied. – Hultén and Fries (1986) and Korobkov (1992) applied the name A. laciniatiformis to northern Asian and American Beringian plants. Korobkov has subsequently concluded that A. laciniatiformis is a narrowly distributed species in Kamtchatka and that this name is inapplicable for the arctic plants (their name is then A. tanacetifolia L.).
Cirsium helenioides (L.) Hill. – Name misapplied. – The name has been applied to the morphologically deviating eastern part of C. heterophyllum in Russia and Siberia. Talavera and Valdés (1976) showed that the type of Carduus helenioides L. (Airy Shaw 1938: 825) belongs to a more southern hybrid and that the northeastern plant is nameless.
Crepis albescens Kuvaev & L.S. Demidova. – Not confirmed to be a taxon. – This is a plant known only from the type collection from Polar Ural in European Russia. It seems close to or conspecific with C. chrysantha (Rebristaya 1987b). Sekretareva (2004) synonymized the name with C. chrysantha.
Erigeron acris L. var. asteroides (Andrz.) DC. – Name misapplied. – The name "asteroides", which has been applied in both Russia and North America (e.g., Porsild and Cody 1980), belongs according to Hultén (1968b) to the non-arctic western Siberian E. podolicus Besser and is inapplicable for the arctic and North American plants. It is replaced by subsp. politus and subsp. kamtschaticus.
Erigeron grandiflorus Hook. – Name misapplied. – All plants assigned under this name from the Arctic (e.g., Hultén 1968a; Porsild and Cody 1980; Petrovsky 1987b) belong to three other Beringian species: E. koraginensis, E. muirii, and E. porsildii. The true E. grandiflorus is a more southern Cordilleran species (Nesom and Murray 2005) described with holotype (GH) from Canada: "Summits of the Rocky Mountains" [probably north of Jasper, Alberta], leg. Drummond, and reported with 2n = 18, 27 (2x, 3x). Spongberg (1971) etc.
Erigeron pallens Cronquist. – Name misapplied. – This name has been applied to American Beringian plants now assigned to E. purpuratus and E. denalii (Nesom and Murray 2005). The true E. pallens is restricted to southern British Columbia and southern Alberta (Cody 1996; Nesom 2006b).
Solidago canadensis L. – Name misapplied. – Semple and Cook (2006) re-assigned to S. lepida the plants from northwestern North America previously assigned to S. canadensis (var. salebrosa, e.g., Hultén 1968a; Porsild and Cody 1980; Cody 1996). The var. salebrosa was considered distinctly not arctic.
Solidago hispida Muhl. ex Willd. – Not arctic. – Scoggan (1979) reported the northernmost sites for S. hispida at Nelson River south of Churchill (Manitoba) and at Severn River at 5545'N (Ontario) in Canada. These localities are boreal and not close enough to be in the Borderline Arctic.


Impatiens capensis Meerb. – Not arctic. – Impatiens capensis replaces I. noli-tangere in most parts of North America, e.g., in the Hudson and James Bay areas. It does not closely approach the Arctic.


Betula occidentalis Hook. – Name misapplied. – The name B. occidentalis has been applied to an American Beringian plant (e.g., Hultén 1968a; Cody 1996). Furlow (1997) considered B. occidentalis a more southern species. The plants in the northwest assigned under this name are more or perhaps rather less stabilized hybrid swarms between B. glandulosa and B. neoalaskana, discussed in the main text under B. neoalaskana.


Cryptantha spiculifera (Piper) Payson. – Misidentified. – This American species has been reported from Senyavin Bay in East Chukotka based on a plant collected by Razzhivin and Yurtsev in 1972 (LE). Ovczinnikova and Nikiforova (2006) re-identified the material as Myosotis alpestris subsp. asiatica. Murray and Elven inspected a duplicate specimen in 2009 and came to the same conclusion.
Lappula deflexa (Wahlenb.) Garcke. – Not arctic. – Petrovsky (PAF proposal) indicated L. deflexa to reach the Arctic in Norway, based mainly on the map by Hultén and Fries (1986). It occurs far north in Norway (several localities in Nesseby municipality) but not close enough to reach the Borderline Arctic.
Mertensia sibirica (L.) G. Don. – Not arctic. – Petrovsky (1980a) reported M. sibirica to reach or almost reach the Arctic in the lower Jenisei River area in Siberia. Nikiforova (1997a) mapped occurrences only much farther south.
Myosotis sparsiflora J.G. Mikan ex Pohl. – Not arctic. – Petrovsky (PAF proposal) accepted M. sparsiflora from the surroundings of Ponoj (the Murman area) and from Kanin–Pechora in European Russia. The Ponoj area is considered boreal, and Chernov (1966) only accepted the species from the southwestern Murman area, far from the Arctic. Neither Martinenko (1977b) nor Petrovsky (1980a) included it from Kanin–Pechora. Hultén and Fries (1986) has a 'dot' along Pechora but well south of the Arctic.
Myosotis sylvatica Hoffm. (s. str.). – Probably misidentified. – Hultén and Fries (1986) mapped M. sylvatica from northern Iceland, close to or within the Arctic. Kristinsson (2008, 2010) did not accept the species (or any close relative) from Iceland.
Phacelia franklinii (R. Br.) A. Gray. – Not arctic. – Scoggan (1979) reported and Porsild and Cody (1980) mapped P. franklinii northwards in Manitoba nearly to Churchill at Hudson Bay, and also reported it far north in the Northwest Territories east of Great Bear Lake. Clear arctic or borderline occurrences are not yet known.


Arabis allionii DC. – Not arctic and/or name misapplied. – Titz (1966 etc.) and Jones and Akeroyd (1993) reported A. allionii to be a diploid species of the A. hirsuta group and to be present in northern Europe. Firstly, we have no records of diploids from or close to the Arctic. Secondly, there is no support for a division of the northern European into two morphologically separable species (diploid and tetraploid).
Arabis borealis Andrz. ex Fisch. & C.A. Mey. – Not arctic. – Arabis borealis (described from Kamtchatka) seems largely to replace A. hirsuta in Asia, has been reported from arctic localities (Doronkin 1994; Titz in several works). It does not seem to reach the Arctic. This name has been misapplied in North America.
Boechera divaricarpa (A. Nelson) Á. Löve & D. Löve. – Name misapplied. – This species has for long been accepted from Alaska and the Yukon Territory. However, the name belongs to a much more southern species, not reaching north to Canada (Al-Shehbaz and Windham 2010). The plant that reaches the Arctic is B. grahamii.
Cardamine conferta Jurtz. – Not arctic. – Löve and Löve (1975a) reported C. conferta to reach the Arctic in the Russian Far East. This is a species of the more southern parts of the Verkhoyansk and Kolyma mountains and does not reach the Arctic.
Cardamine hirsuta L. – Probably misidentified. – Hultén and Fries (1986: map 935) mapped two arctic occurrences of Cardamine hirsuta in Manitoba, at the western shore of Hudson Bay. Scoggan (1978c) did not mention these occurrences. The records might belong to C. oligosperma subsp. kamtschatica or C. pensylvanica. However, the species is recorded as casual in Iceland (see above).
Cardamine parviflora L. – Probably misidentified. – Hultén and Fries (1986: map 932) mapped arctic occurrences of C. parviflora west of Hudson Bay in Manitoba. Neither Scoggan (1978c) nor Rollins (1993) accepted these records. The records might belong to C. oligosperma subsp. kamtschatica or C. pensylvanica.
Cardamine pedata Regel & Tiling. – Not arctic. – Löve and Löve (1975a) reported C. pedata to reach the Arctic in the Russian Far East. This is a local species of the Okhotsk–Ayan region and does not penetrate the Arctic.
Draba aleutica E. Ekman. – Not arctic. – Löve and Löve (1975a) reported D. aleutica to reach the Arctic in the Bering Sea area. This species is, as far as known, restricted to the more southern Bering Sea islands and coasts. It approaches the Arctic in mainland southwestern Alaska but not close enough to be in the Borderline Arctic.
Draba baicalensis Tolm. – Name probably misapplied. – Russian sources report D. baicalensis to reach the Arctic in West Chukotka. Petrovsky commented that D. baicalensis s. str. does not occur in Chukotka. The plants assigned under this name may belong or be related to D. yukonensis G.A. Mulligan and should be inspected anew.
Draba lanceolata Royle. – Name misapplied. – Draba lanceolata has often been reported from the Arctic, in both Eurasia and North America. This is a central and southern Asian alpine species. The records from European Russia mostly refer to D. incana, those from Siberia, North America, and Greenland mostly to D. cana.
Draba ogilviensis Hultén. – Not arctic. – Draba ogilviensis is a species related to D. sibirica and restricted to the Ogilvie Mountains on the border between Alaska and the Yukon Territory and the Richardson and the Wrangell–St. Elias mountains, all south of the Arctic (Murray and Parker 1999).
Draba paysonii J.F. Macbr. – Not arctic. – Löve and Löve (1975a) reported D. paysonii to reach the Arctic in Canada. Cody (1996) only accepted this Cordilleran species north to east–central Alaska and the southwestern Yukon Territory, south of the Arctic.
Draba porsildii G.A. Mulligan. – Not arctic. – Löve and Löve (1975a) reported D. porsildii to reach the Arctic in Canada, possibly in the Brooks Range in northern Alaska. The northernmost finds for which we have found documentation of this Cordilleran species are well south of Arctic in east–central Alaska.
Draba praealta Greene. – Not arctic. – Draba praealta has occasionally been reported from the Arctic in western and northern Alaska but we have seen no supporting specimens. We have seen a few specimens (ALA) from non-arctic southeastern Alaska and the central Yukon Territory. Cody (1996) mapped it only north to the non-arctic central Yukon Territory.
Draba ruaxes Payson & H. St.John. – Not arctic. – A North American species sometimes reported to reach the Arctic but which seems to stop well south of the boundary.
Draba sambukii Tolm. – Not confirmed as a taxon. – This species is reported from Taimyr in Siberia but only known with certainty from a now disappeared type collection. Of the other specimens assigned under this name, the more recently collected ones probably are defective specimens of D. glabella, whereas at least parts of the older ones belong to D. lactea.
Draba villosula Tolm. – Not arctic. – Löve and Löve (1975a) reported D. villosula from northeastern Siberia. Tolmachev (1975b) did not mentioned it from there. It does not reach the Arctic according to Petrovsky.
Noccaea (Thlaspi) cochleariforme (DC.) Á. Löve & D. Löve. – Name applied differently. – This is a more southern plant in our opinion. We assign the plants that reach the Arctic to N. arctica.
Rorippa curvisiliqua (Hook.) Bessey ex Britton. – Not arctic. – Hultén (1968a) mapped this species, as R. palustris var. occidentalis (S. Watson) Rollins, from southern Alaska westwards to the Arctic or near arctic parts of the Goodnews Bay. Hultén and Fries (1986) omitted this part of its range.


Lonicera caerulea L. subsp. kamtschatica (Sevast.) Gladkova. – Not arctic. – Gladkova (1987) reported this race from South Chukotka. It is not yet known to reach the Arctic or the Borderline Arctic.
Symphoricarpos albus (L.) S.F. Blake subsp. albus. – Not arctic. – Hultén (1968a) mapped S. albus to nearly reach the Arctic in the Hudson Bay area. Porsild and Cody (1980) did not map it from the Arctic. Scoggan (1979) did not mention any arctic localities. The western North American subsp. laevigatus (Fernald) Hultén reaches only north to non-arctic southeastern Alaska.


Atocion rupestre (L.) Oxelman (Silene rupestris L., Minjaevia rupestris (L.) Tzvelev). – Not arctic. – Atocion rupestre approaches the Arctic in Norway (Hultén 1971b; Hultén and Fries 1986) but probably not close enough to reach the Borderline Arctic.
Cerastium arcticum Lange var. sordidum Hultén. – Not a taxon. – Hultén (1956) mapped var. sordidum as a major race of C. arcticum, whereas Morton (2005a) synonymized Hultén's var. sordidum with his C. bialynickii. The type belongs to the quite frequent, sterile hybrid C. arcticum x regelii. The other material that Hultén assigned to this variety belongs within the large and not well structured polymorphy of C. arcticum.
Silene menziesii Hook. subsp. williamsii (Britton) Hultén. – Not arctic. – This species occurs according to Hultén (1968a) in northeastern Alaska north to the Porcupine River. No record from the Arctic is found (ALA).
Silene soczavana (Schischk.) Bocquet var. soczavana. – Not arctic. – Bezdeleva (1966) reported S. soczavana s. str. from the Anadyr River drainage in South Chukotka. It has not yet been found in the Arctic.
Stellaria alsine Grimm. – Probably misidentified. – Hultén and Fries (1986) mapped S. alsine from a few localities on the southwestern side of Hudson Bay. The records are probably based on misidentifications. However, there is a chromosome number report by Löve and Löve (1982a) from Churchill in Manitoba. Morton (2005b) excluded occurrences in the Arctic of Quebec, Ontario, and Manitoba (i.e., Hudson Bay). No specimens supporting an occurrence there were found in the CAN herbarium (in 2009).
Stellaria arenicola Raup. – Probably misidentified. – Stellaria arenicola was described from Lake Athabasca in Saskatchewan and is, according to Chinnappa and Morton (1991), a local race (of S. longipes) only known from the type area. We have therefore excluded the reports from Chukotka (Zhukova and Petrovsky 1977, chromosome count of 2n = 72; Antonova and Petrovsky 1986).


Sedum cyaneum Rudolph. – Not arctic. – Petrovsky (1984) reported S. cyaneum from the Anadyr area in South Chukotka. The northernmost mapped locality (Bezdeleva 1995) lies south of the Arctic.


Carex atratiformis Britt. subsp. raymondii (Calder) A.E. Porsild. – Probably not arctic. – This species goes far north in Alaska and Canada but probably not close enough to reach the Borderline Arctic.
Carex glareosa Wahlenb. subsp. pribylovensis (J.M. Macoun) G. Halliday & Chater (C. pribylovensis J.M. Macoun). – Probably not arctic. – Egorova (1966a) reported this race from arctic St. Lawrence Island in western Alaska. According to Murray it is unlikely to occur on St. Lawrence Island. It occurs on (and was described from) the Pribilof Islands.
Carex magellanica Lam. – Name applied differently. – We consider the northern plants as C. paupercula Michx. (see that species in the main text) and specifically different from the South American C. magellanica.
Carex oederi Retz. – Name misapplied. – This name has previously very often been applied to a widespread species of sect. Ceratocystis, more lately mostly considered in Europe as C. serotina Mérat, in North America as C. viridula Michx. Egorova (1999) showed that the name C. oederi is a synonym of the only distantly related C. pilulifera.
Carex parryana Dewey. – Not arctic. – Hultén (1968a) mapped C. parryana from just inside the Arctic in the Brooks Range in northern Alaska. Murray stated that this species is not present in northern Alaska according to the Flora of North America documentation. The type – from "Hudson's Bay" – was according to Scoggan (1978b) probably collected in boreal areas west of Hudson Bay.
Carex pellita Willd. – Not arctic. – Hultén (1968a) mapped this species (as C. lanuginosa) within or very close to the Arctic on the southern side of Hudson Bay. Scoggan (1978b) did not report such northern occurrences and neither did Ball (in comment).
Carex stenolepis Less. – Possibly not a taxon and probably not arctic. – Carex stenolepis was described from the Trondheim area in central Norway and Torne lappmark in northern Sweden. Plants conforming to this description are frequent in and along the Scandinavian mountains and have been reported by several sources to reach the Arctic in Norway and northwestern European Russia. We have recently checked the northern material and have not recorded any certainly arctic occurrences.
Carex stenolepis has sometimes been accepted as species (e.g., Chater 1980; Elven 1994) but more often it has been interpreted as a not fully stabilized hybrid swarm between C. saxatilis and C. vesicaria. Two features count against a simple hybrid situation: (a) It was originally described partly from an area where C. saxatilis is absent (the Trondheim area) and it often occurs in the absence of one or both putative parents (C. saxatilis in firm, short-sward mires, C. stenolepis in lush, tall-sward mires, and C. vesicaria in swamps). (b) In the Norwegian material, the largely pollen-fertile C. stenolepis differs morphologically from and is much less polymorphic than the more obviously pollen-sterile hybrid C. saxatilis x vesicaria. Carex stenolepis at least sometimes produces well-formed perigynia. Egorova and Elven are both in doubt whether to accept C. stenolepis. Ball commented that Ford looked at a large number of specimens labelled as C. stenolepis, including material from the type region(s). Although some specimens have well-formed perigynia that even apparently contain achenes, the achenes are invariably empty. He was unable to find any plants which had mature well-formed achenes. Carex stenolepis is therefore, until further investigations, omitted as possibly being a hybrid swarm without independent existence and also without well documented arctic occurrence.
Eleocharis acicularis (L.) Roem. & Schult. subsp. yokoscensis (Franch. & Sav.) T.V. Egorova. – Misidentified. – Bubovna (1990b) reported this race from arctic or near-arctic parts of Siberia. Egorova inspected the relevant specimens (in the NS herbarium) and assigned them to subsp. acicularis.
Eriophorum altaicum Meinsh. – Name misapplied. – Löve and Löve (1975a) and other authors have applied this name to an arctic species. The name belongs, according to Novoselova (1993, 1994), to a much more southern species. The Löves may have misapplied this name to E. chamissonis.
Rhynchospora alba (L.) Vahl. – Not arctic. – Porsild and Cody (1980) mapped this species close to the Arctic in Ontario, at the southern Hudson Bay just west of the mouth of James Bay. Scoggan (1978b) reported no clearly arctic localities. According to Ball, Riley does not accept this species from the Arctic of Ontario, only from the subarctic wathersheds.
Schoenoplectus americanus (Pers.) Volkart. – Name misapplied. – Scoggan (1978b) and other sources have reported this species from Fort Severn at the southern Hudson Bay in Ontario. Smith commented that this is a misinterpretation of the species which is much more southern. The relevant material belongs, according to him, to S. pungens.
Schoenoplectus tabernaemontani (C.C. Gmel.) Palla. – Name applied differently. – This species has been reported from the Hudson Bay area. Smith et al. (2002) considered the American S. validus (basionym published Oct.–Dec. 1805) to be the same species as the Eurasian S. tabernaemontani (C.C. Gmel.) Palla, Verh. K. K. Zool.–Bot. Ges. Wien 38 (Sitzungsber.) 49 (1888) (basionym: Scirpus tabernaemontani C.C. Gmel., Fl. Bad. 1: 101, published Apr.–May 1805). The latter name then has priority at species level. He described it as "one variable, cosmopolitan species without infraspecific taxa, pending further studies". We have retained S. validus as an American taxon different from S. tabernaemontani, following, e.g., Hultén and Fries (1986), and thereby exclude S. tabernaemontani from the Checklist as it is distinctly non-arctic in Eurasia.
Trichophorum pumilum (Vahl) Schinz & Thell. – Probably not arctic. – This species occurs on dolomite outcrops and seepage in Finnmark in northernmost Norway, northwards almost to within sight of the Arctic, but still not close enough to be in the Borderline Arctic. It has, however, been largely overlooked in Norway and is frequently found in new localities. It has not yet been efficiently searched for in the several sites with dolomite bedrock in arctic Norway.



Dryopteris abbreviata (DC.) Newman ex Manton. – Name misapplied. – Böcher et al. (1978) and other sources have reported this European species from Greenland. The records belong to the American D. marginalis.
Dryopteris dilatata (Hoffm.) Gray. – Name misapplied. – Older records under this name from arctic and northern parts almost uniformly refer to D. expansa.


Elaeagnus commutata Bernh. ex Rydb. – Not arctic. – This easily recognized and never overlooked species has been reported from Hudson Bay by both Porsild and Cody (1980) and Scoggan (1979), the latter from "20 mi SW of York Factory ... and northernmost Ont[ario]". Both records are outside the Arctic.


Equisetum x litorale Kühlew. ex Rupr. – Not a taxon. – Equisetum x litorale is the hybrid E. arvense x E. fluviatile and is reported from arctic localities in European Russia, Siberia, Alaska, and Canada. It spreads vegetatively but has been reported only with abortive spores and does not occur independent of its parents.


Arcterica nana (Maxim.) Makino. – Erroneous record. – The record from the Lena River Delta in northern Siberia is, according to Yurtsev (in comment), an evident mistake based on mixed herbarium labels (in the herbarium MW).
Cassiope x anadyrensis Jurtz. (C. ericoides (Pall.) D. Don x tetragona (L.) D. Don). – Not confirmed as a taxon. – Yurtsev (1980b) considered C. x anadyrensis a hybrid species and reported it from the Russian Far East, sometimes represented by populations with an intermediate ecology. Its independence from its parents is not confirmed.
Pyrola rotundifolia L. – Probably not arctic. – Kobeleva (1977) reported P. rotundifolia to reach the Arctic in Kanin–Pechora in European Russia. Hultén and Fries (1986, as subsp. rotundifolia) mapped it from the Borderline Arctic by shading all the woodland areas of northeastern Europe along with the valley of the Jenisei River north to 69N ('dots' are not given). Confirming material has not been seen but plants resembling this species were collected in 2004 along arctic parts of the lower Lena River.
Rhododendron x vanhoeffenii (Abrom.) (X Ledodendron vanhoeffenii (Abrom.) Dalgaard & Fredskild). – Not a taxon. – This Greenland plant is a primary hybrid between Rhododendron lapponicum and R. tomentosum subsp. decumbens, possibly with some local vegetative spread, but without efficient reproduction and with no independence from its parents. See Dalgaard and Fredskild (1993): "All plants are completely seed sterile, containing aborted seeds only". Also found to be nearly fully pollen sterile.


Astragalus australis (L.) Lam. – Name applied differently. – Numerous authors (especially American ones, e.g., Barneby 1964; Cody 1996; Gillett et al. 2007) have applied this name collectively to a large group of alpine and arctic plants. We consider the northern plants to belong to several species, all different from the central and southern European A. australis s. str.
Astragalus striatus Nutt. ex Torr. & A. Gray. – Not arctic. – Yurtsev (PAF proposal) reported A. striatus to reach the Arctic in Canada. The occurrences mapped by Porsild and Cody (1980) are south of the Arctic. The closest occurrence is, according to Scoggan (1978c) in Manitoba at Gillam ca. 165 miles south of Churchill.
Hedysarum alpinum L. s. str. – Name applied differently. – We regard the northwestern North American plants as H. americanum and as specifically distinct from the non-arctic Asian H. alpinum s. str. (Kurbatskij 1994a).
Hedysarum alpinum L. subsp. boreoeuropaeum Jurtz. – Not arctic. – Hultén and Fries (1986: map 1256) mapped this taxon from the Arctic in the Malozemelskaya and Bolshezemelskaya tundras in European Russia. Kobeleva (1976c) mapped it as much more southern and Yurtsev (1986) did not include it for the Arctic. There is obviously a discrepancy in concepts and we here rely on Yurtsev's.
Oxytropis middendorffii Trautv. subsp. trautvetteri (Meinsh.) Jurtz. – Not arctic. – This subspecies was tentatively reported by Yurtsev (PAF proposal) from South Chukotka. The material from there is of dubious identity. Pavlova (1989) did not accept any reports from South Chukotka or nearby areas.
Vicia multicaulis Ledeb. – Not arctic. – Vicia multicaulis approaches the Arctic in the lower reaches of the Lena River in northern Siberia but does not reach it, see map in Yurtsev (1986) and Nikiforova (1987b).


Corydalis pauciflora (Willd.) Pers. – Name applied differently. – The majority of authors until the 1990s have applied this name to a widespread northeastern Asian and Beringian plant. We follow Lidén and Zetterlund (1997), regard C. pauciflora as a species of southern Siberia and central Asia, and assign all arctic material to C. arctica Popov.


Swertia perennis L. – Name applied differently. – The name S. perennis has been nearly uniformly applied to a northwestern North American plant (e.g., Hultén 1968a; Cody 1996) but the plant is S. obtusa, described from northwestern North America. Swertia perennis s. str. is restricted to central and southern Europe.


Geranium albiflorum Ledeb. – Name applied differently. – This name has been widely applied to a northeastern European Russian and northwestern Siberian plant (e.g., Webb and Ferguson 1968). Tzvelev (1993) described the northern plant as G. krylovii, specifically different from the more southern G. albiflorum described from the Altai in Kazakhstan. Peschkova (1996a) accepted this treatment for Siberia, as we do.


Ribes rubrum L. – Name misapplied. – This name has often been applied to the northern native Ribes in Europe. It belongs to a western European species (the garden Red Currant) that only occurs as an occasional escape in northern Europe. It has not been recorded from the Arctic. The native northern plant to which the name has been applied is R. spicatum.


Myriophyllum spicatum L. – Name misapplied. – Kristinsson (2010) reported M. spicatum from the Arctic in Iceland, whereas he did not report M. sibiricum. All inspected Icelandic plants belong to M. sibiricum.


Elodea canadensis Michx. – Not arctic. – Elodea canadensis has been mapped to approach or reach the Arctic on the southern side of Hudson Bay (Hultén and Fries 1986: map 94). Scoggan (1978b) reported it only north to Reindeer Lake in Manitoba, 5754'N, well inside the boreal. Haynes (2000a) did not map any arctic North American localities, only occurrences at the boreal James Bay where also the related E. nuttallii (Planch.) H. St.John was mapped.


Hypericum maculatum Crantz. – Not arctic. – Hypericum maculatum approaches the Arctic in Norway and in the Bolshezemelskaya Tundra in European Russia but is probably only found distinctly south of boundary. The plant that approach the Arctic is subsp. maculatum.


Juncus effusus L. – Not confirmed as arctic. – Hultén and Fries (1986: map 195) recorded J. effusus at York Factory on the southern side of Hudson Bay, on the authority of Macoun 1888. This record was not fully accepted by Scoggan (1978b), nor included by Hämet-Ahti (1980a) in her treatment of the J. effusus aggregate in eastern North America or in the map by Kirschner et al. (2000c), but was included in the map by Brooks and Clemants (2000).
Juncus leschenaultii J. Gay ex Laharpe. – Misidentified. – Tikhomirov and Gavrilyuk (1966) reported this species from the Chaplino Hot Springs on the southeastern Chukchi Peninsula, East Chukotka. Also Hultén (1968a, 1973) accepted it from there. Egorova and Yurtsev have re-examined the material and found it to belong to J. alpinoarticulatus.
Juncus pelocarpus E. Mey. – Not arctic. – Brooks and Clemants (2000) mapped J. pelocarpus from James Bay in Canada but south of the Arctic.
Luzula acuminata Raf. – Not confirmed as arctic. – Swab (2000) mapped L. acuminata from the vicinity of Churchill at the southwestern side of Hudson Bay, Manitoba. This might be an inland, non-arctic locality. Kirschner commented that L. acuminata is a woodland species and he could not imagine it being a member of the arctic flora. McJannet et al. (1993) did not include this species, which probably means that they did not accept it to reach the Arctic.
Luzula congesta (Thuill.) Lej. (L. multiflora (Ehrh.) Lej. subsp. congesta (Thuill.) Arcang.). – Misidentified? – Hultén and Fries (1986: map 174) mapped L. congesta throughout Iceland, including the arctic parts. Kirschner commented that the taxon occurs in Iceland but not in the Arctic and perhaps only as introduced with fodder. We (Elven and Solstad) have not seen material of L. congesta in the two major Icelandic herbaria (AMNH, ICEL). The majority of the Icelandic material of L. multiflora deviates morphologically from mainland European material but not in the direction of L. congesta.
Luzula divaricata S. Watson (L. parviflora (Ehrh.) Desv. subsp. divaricata (S. Watson) Hultén). – Name misapplied. – The application of this name to Alaskan plants (e.g., Hultén 1943b, 1968a) was erroneous as pointed out by Kirschner (in comment). The true L. divaricata is a Californian endemic.


Pinguicula vulgaris L. subsp. macroceras (Link) Calder & R.L. Taylor. – Misidentified. – Casper (1966) mapped this race into the Arctic in Alaska, probably based on misidentifications. Hultén (1968a) mapped it only from the non-arctic southern coast. No specimens of subsp. macroceras supporting arctic occurrence have been found (ALA).


Gagea granulosa Turcz. – Not arctic. – Löve and Löve (1975a) reported G. granulosa to reach the Arctic in northeastern European Russia. It does not reach the Arctic in Europe according to Kobeleva (1976a).
Gagea lutea (L.) Ker Gawl. – Not arctic. – Several sources report G. lutea from the surroundings of Ponoj in the Murman area, European Russia. We have excluded Ponoj and its near surroundings from the Arctic.


Diphasiastrum tristachyum (Pursh) Holub (Lycopodium tristachyum Pursh). – Name misapplied. – Many Russian sources have accepted D. tristachyum from the Arctic in European Russia. According to Hultén and Fries (1986) and Jalas and Suominen (1972), these reports from northern regions should be referred to D. complanatum subsp. montellii. Tzvelev (in comment) accepted that conclusion.


Nuphar lutea (L.) Sm. – Misidentified. – Rebristaya (PAF proposal) reported N. lutea to reach the Arctic in the Murman area, European Russia. The species has been reported from the same area by earlier sources. The material behind these reports belongs to N. pumila.


Epilobium alpinum L. – Name misapplied and rejected. – Many Russian author (as late as Tzvelev 2007b) have applied this name as the priority one for the species considered as E. anagallidifolium Lam. in the main text. The designated lectotype belongs to E. lactiflorum Hausskn. The name E. alpinum has been rejected by ICBN.
Epilobium ciliatum Raf. subsp. watsonii (Barbey) Hoch & P.H. Raven (E. watsonii Barbey). – Name misapplied. – The name E. watsonii has been applied to northern (adventive) plants in Europe (e.g., Kristinsson 1987; Elven 1994). According to Hoch (in comment), subsp. watsonii is a local coastal Californian race and the name has been misapplied elsewhere.
Epilobium leptophyllum Raf. – Not arctic. – Hultén (1968a) mapped this species very close to the Arctic on the southeastern side of Hudson Bay in Quebec but Porsild and Cody (1980) did not accept it from there.


Ophioglossum vulgatum L. – Name misapplied. – Hultén and Fries (1986) mapped O. vulgatum from eastern Greenland and from non-arctic parts of Iceland. Tzvelev (PAF proposal) accepted it as an arctic plant. The Iceland and Greenland plant in question has for a long time been known to belong to O. azoricum, not O. vulgatum (e.g., Löve and Kapoor 1967a; Löve 1970a; Einarsson et al. 1996; Jonsell 2000d; Kristinsson et al. 2007; Kristinsson 2010).


Hammarbya paludosa (L.) Kuntze. – Not arctic. – Rebristaya (PAF proposal) reported H. paludosa to reach the Arctic in Alaska. No documentation of arctic occurrence has been found.
Limnorchis convallariaefolia (Fisch. ex Lindl.) Rydb. – Probably erroneous record. – Hultén (1968a) mapped L. convallariaefolia (as a Platanthera) from one isolated locality on the Seward Peninsula in western Alaska. No material has been seen confirming this occurrence and it is improbable.


Euphrasia officinalis L. – Name misapplied. – Euphrasia officinalis has been applied in northern Europe as a fairly collective name to large-flowered and usually stipitate-glandular species. The name is irrelevant for the large-flowered plants that reach the Arctic. It may be a priority name for the eastern European E. rostkoviana Hayne.


Papaver alboroseum Hultén. – Not arctic. – This species has been suggested to reach the Arctic in southwestern Alaska. All known occurrences are west and south of the arctic boundary. The range is boreal on the Asian side as well.
Papaver anadyrense V.V. Petrovsky. – Not arctic. – This species has been suggested to reach the Arctic in South Chukotka. The known occurrences, on ultrabasic rocks, are boreal.
Papaver microcarpum DC. subsp. ochotense (Tolm.) Tolm. (P. ochotense Tolm.). – Not arctic. – Petrovsky (PAF proposal) reported subsp. ochotense to reach the Arctic in South Chukotka but it is boreal there.


Pentstemon gormani Greene. – Not arctic. – Penstemon gormanii occurs north to the southern parts of the northeastern Brooks Range in Alaska (Hultén 1968a; Porsild and Cody 1980) but seems to be confined to the forest belt on the southern slopes, i.e., boreal.
Plantago asiatica L. – Name misapplied. – Hultén (1971a) and Hultén and Fries (1986) applied this name to a Plantago related to P. major in the Beringian regions, especially in Alaska. These plants deviate from European P. major but not in the direction of the much more southern Asian P. asiatica.
Plantago juncoides Lam. – Name applied differently. – We regard the northern plants parts of P. maritima and as different from the South American P. juncoides.


Agrostis trinii Turcz. – Name applied differently. – This name has been widely applied to an amphi-Beringian species (e.g., Tzvelev 1964f; Hultén 1968a; Cody 1996). Tzvelev (in comment) considers the plant that reaches the Arctic to belong to A. kudoi, different from the southeastern Siberian A. trinii.
Bromopsis pumpelliana (Scribn.) Holub subsp. ircutensis (Kom.) Tzvelev (Bromus ircutensis Kom.). – Not arctic. – Tzvelev (PAF proposal) reported subsp. ircutensis from West Chukotka as rare. Neither Peschkova (1990c, Siberia) nor Probatova (1985, the Russian Far East) report occurrence in or close to the Arctic. Peschkova accepted three species within what has been named as B. ircutensis Kom.: B. karavajevi (Tzvelev) Czerep., B. korotkiji (Drobow) Holub (= B. ircutensis Kom.), and B. pavlovii (Roshev.) Peschkova, all restricted to southern to southeastern Siberia and central Asia.
Calamagrostis chordorrhiza A.E. Porsild. – Probably not a taxon. – Calamagrostis chordorrhiza was described with type from Canada: the Northwest Territories, the Mackenzie River Delta, "hill back of Reindeer Station".

Aiken: This species should not be accepted. The single record from the Arctic Archipelago in Porsild (1957) suggests that this taxon was collected at Mould Bay, Prince Patrick Island. A possible voucher specimen is at DAO and was annotated as C. stricta by C.W. Greene in 1980 [Elven: probably C. neglecta subsp. groenlandica]. The type specimen of C. chordorrhiza (see above) was examined by Greene in 1987 and annotated as C. stricta approaching subsp. inexpansa. No other specimens to which the name C. chordorrhiza might be applied have been found. See Greene (1984).

Elven: Soreng et al. (2003) included the name C. chordorrhiza in the synonymy of C. stricta [C. neglecta] subsp. inexpansa. However, a specimen from the type site (ALA) combines features of the sexual tetraploids C. holmii and C. neglecta subsp. groenlandica and shows aborting anthers. There is no report on pollen fertility in the type specimen. The same hybrid is not uncommon in northern and northwestern Alaska. In all probability, the name C. chordorrhiza belongs to this hybrid. It has not been ascertained whether it occurs only as sterile hybrid clones (i.e., not a taxon) or with agamospermous reproduction.

Calamagrostis kolymaensis Kom. – Probably not a taxon. – Calamagrostis kolymaensis is reported to reach the Arctic in Yana–Kolyma, West, East, and South Chukotka, and Wrangel Island. Tzvelev (PAF proposal) suggested it to be a hybrid species from the sexual tetraploids C. deschampsioides and C. holmii. The chromosome numbers reported for C. kolymaensis are tetraploid (2n = 28, Zhukova and Petrovsky 1975, West Chukotka; Packer and McPherson 1974, northern Alaska, according to Löve and Löve 1975a, but the species has not been accepted from North America), and hexaploid (2n = 42, Zhukova and Petrovsky 1975, West Chukotka; Petrovsky and Zhukova 1981, Wrangel Island). The material we have inspected of C. kolymaensis (ALA) clearly suggests a hybrid as above, with intermediate morphological features and aborting anthers. Stabilized hybrids at tetraploid level are unknown among arctic Calamagrostis, whereas the hexaploid might be an agamospermic hybrid derivate. In views of the doubts, C. kolymaensis is excluded.

Deschampsia glauca Hartm. – Name misapplied. – A majority of authors have considered D. glauca a native boreal–arctic species (or subspecies of D. cespitosa) widespread throughout European Russia, Siberia, the Russian Far East, and North America. The name is based on a Scandinavian plant and has been used in at least three meanings (I–III), two of which probably have no relevance for arctic plants:

  1. The holotype (UPS!) for the name Deschampsia glauca Hartm. must be: "Aira glauca. Specimen ex typum. (Frösö) e Jemtlandia, 1818", Hartman (scripsit), Herb. E. Fries, i.e., from Frösön at lake Storsjön in Jämtland, north–central Sweden. This specimen deviates from D. 'glauca' as it later has been considered by Nordic authors, especially by Gunnar Samuelsson who revised large parts of the material. It has stout awns, large and coarse panicles, and very long, thick, convolute leaves. The plant much resembles some of the many Scandinavian modifications of D. cespitosa s. str. and it grows on a southern boreal lake shore. The similarity with the plant denoted as D. glauca in Russia, Siberia, and North America is slight.
  2. What currently goes by the name D. cespitosa subsp. glauca in Scandinavian literature is a rather different river and lake shore plant with very thin convolute leaves, very slender culms, open and delicate panicles, very slender awns, and distinctly shorter anthers than D. cespitosa s. str. This plant seems to be confined to some of the larger southern and eastern Scandinavian river and lake systems and seems to keep distinct from subsp. cespitosa which also is common on the same shores and even occur in mixed populations. The tentative Nordic conclusion is that this is a regional race: an ecologically very narrow plant in central Sweden and southeastern Norway, rarely reaching the northern boreal zone and certainly not the Arctic. It has consistently been named 'glauca' by Scandinavian authors. It differs from the type but is frequent on the shores of lake Storsjön from where D. glauca Hartm. was described. The type specimen of D. glauca may be a very coarse plant of this taxon. The plants commonly named as 'glauca' in Scandinavia do not have have much similarity with what the Russians and North Americans have named as D. glauca.
  3. A plant named 'glauca' from Torneträsk in Torne lappmark, northern Sweden, is different both from Hartman's D. glauca and from the filiform-leaved plant currently considered as subsp. glauca. Material from there has been widely distributed in exsiccates and may have formed the non-Scandinavian opinion of what D. glauca should be. It is a fairly coarse plant with short, stiff and not very convolute leaves and a dense and often strongly pigmented panicle. It is northern boreal to alpine and is much more similar to D. cespitosa s. str. than is the Scandinavian subsp. glauca (entity II). We suspect that this plant may have influenced the application of the name 'glauca' in Russian literature. In Scandinavian literature it has often been named as 'brevifolia' (and it is 'brevifolious'), but it has little to do with Robert Brown's arctic Canadian D. brevifolia. Its relations are probably distant with what is accepted in the main text as D. anadyrensis.

Deschampsia mackenzieana Raup (D. cespitosa var. mackenzieana (Raup) B. Boivin). – Probably not arctic. – This is a striking plant that occurs in the Northwest Territories, mainly along the Mackenzie River downstream to Inuvik, but not yet confirmed to reach the Arctic (even if it is very close). Soreng et al. (2003) accepted it as a variety of D. cespitosa. If D. cespitosa s. str. is European and western Siberian, as we assume, D. mackenzieana is probably either a separate species or a race of another, North American species.
Elymus trachycaulus (Link) Gould ex Shinners subsp. andinus (Scribn. & J.G. Sm.) Á. Löve & D. Löve. – Name misapplied and not a taxon. – Hultén (1968a) reported subsp. andinus to reach the Arctic in Alaska but Dewey (1963) and Barkworth et al. (2007) assigned the name 'andinus' to the hybrid between E. trachycaulus and the much more southern E. scribneri (Vasey) M.E. Jones, only reported to reach north to southwestern Alberta.
Festuca diffusa Dum. – Erroneous report. – Markgraf-Dannenberg (1980) reported F. diffusa from Svalbard without any documentation. The record is obviously erroneous as this is a temperate and thermophilous segregate of the F. rubra group, more often considered as F. rubra subsp. megastachys Gaudin.
Festuca hallii (Vasey) Piper. – Erroneous report. – Tzvelev (PAF proposal) accepted this species from western Alaska. Aiken commented that F. hallii is a prairie taxon that does not approach the Arctic anywhere.
Festuca polesica Zapal. – Probably misidentified. – Skvortsov (1964) reported F. polesica to reach the Arctic in the Malozemelskaya Tundra in European Russia. Tolmachev (1977) accepted it from there as F. beckeri subsp. sabulosa. These reports are improbable and now doubted both by Tzvelev and Elven, but we do not know the characters of the material they are based on.
Festuca prolifera (Piper) Fernald. – Not confirmed as a taxon. – Festuca prolifera is a bulbil-reproducing counterpart of F. rubra. Tzvelev (PAF proposal, based on Alexeev's studies) recognized F. prolifera to reach the Arctic only in Greenland, probably because the plants in other areas were considered by him and by Alexeev as F. villoso-vivipara (see below) with a different putative parentage. Aiken commented that the name F. prolifera in Canada has been assigned only to scattered specimens of bulbil-reproducing F. rubra. As its origin probably is highly polyphyletic, sometimes involving one ploidy level in F. rubra, sometimes perhaps two, and perhaps occasionally F. ovina, we do not see it as a coherent taxon. However, Soreng et al. (2003) accepted this taxon.
Festuca rubra L. subsp. arenaria (Osbeck) F. Aresch. (F. arenaria Osbeck). – Name misapplied. – Festuca arenaria or subsp. arenaria has repeatedly been reported to reach the Arctic in Kanin–Pechora in European Russia. In the type meaning, subsp. arenaria is octoploid (2n = 56, Kjellqvist 1964, Sweden, Denmark, western Europe, ca. 300 plants from 47 populations) vs. hexaploid (2n = 42) in F. rubra s. str. and subsp. richardsonii, and a morphologically distinct race or species restricted to temperate northwestern European sand dunes, very far from the Arctic (see Kjellqvist 1964). However, the name 'arenaria' has until fairly recently been widely applied to the major arctic race (subsp. richardsonii or subsp. arctica) due to the common feature of hairy lemmas. All checked records of F. arenaria or F. rubra subsp. arenaria from the Arctic are referrable to F. rubra subsp. richardsonii.
Festuca rubra L. subsp. aucta (V.I. Krecz. & Bobrov) Hultén. – Not confirmed as a taxon. – Hultén (1968a) indicated subsp. aucta with a question mark from East Chukotka and mapped it from western (arctic) and southern Alaska. Tzvelev is very skeptical to this taxon and comments that it does not really exist, with reference to Probatova (1985). However, there are complications in the F. rubra aggregate in the North Pacific and Beringian regions not yet solved.
Festuca rubra L. subsp. fraterculae (Rasm.) Á. Löve & D. Löve. – Not confirmed as a taxon. – Subspecies fraterculae was described from the Faeroe Islands as a bird cliff race and reported by Löve and Löve (1956b, 1975a) to reach the Arctic in Iceland, by Pedersen (1972: 40) in southern Greenland. We tend to see this rather as a series of manured bird cliff ecotypes, i.e., not as a coherent taxon. The abundant bird cliff populations of F. rubra in arctic mainland Norway, Bear Island, and Spitsbergen do not belong morphologically within this taxon.
Festuca villoso-vivipara (Rosenvinge) E. Alexeev. – Not confirmed as a taxon. – Alexeev (1985) and Tzvelev (PAF proposal) considered F. villoso-vivipara a hybrid species from F. rubra s. lat. x F. vivipara s. lat. Tzvelev reported it from Greenland but it occurs also in Iceland and Scandinavia with several chromosome numbers: 2n = (1) 28 (4x), Tzvelev's PAF proposal; (2) 35 (5x), Frederiksen (1981, Iceland); (3) 42 (6x), Knaben and Engelskjøn (1967, Norway), Engelskjøn (1979, Norway); (4) 49 (7x), Flovik (1938), Löve and Löve (1956b, Iceland), Frederiksen (1981, Iceland), Salvesen in Engelskjøn (1979, Norway); and (5) 63 (9x), Knaben and Engelskjøn (1967, Norway), Salvesen in Engelskjøn (1979, Norway). Frederiksen (1981) was skeptical to this entity as a taxon as is Elven. It is interpreted in Fennoscandia as single cases of hybridization between F. rubra and the sexual F. ovina (not the bulbil-reproducing F. vivipara with very little sexuality), often resulting in clones due to the bulbils (and short runners), but without a consistent range or ecology. The reported chromosome numbers mostly refer to such plants. Elven argues that such occasional hybrids and bulbil-reproducing hybrid clones should not be accepted as a taxon. Tzvelev comments that he accepts and relies on Alexeev's treatment, i.e., acceptance of also F. villoso-vivipara as species.
Glyceria triflora (Korsh.) Kom. (G. arundinacea (M. Bieb.) Kunth subsp. triflora (Korsh.) Tzvelev). – Not arctic. – Löve and Löve (1975a) reported G. triflora to reach the Arctic in Siberia. Tzvelev commented that he considers it very closely related to and perhaps conspecific with G. grandis and, in addition, probably not arctic.
Hierochloe hirta (Schrank) Borbás subsp. praetermissa G. Weim. – Not arctic. – Weimarck (1986) reported subsp. praetermissa from Russia "in the N–S direction from the N Ural mountains to Tyan Shan". Tzvelev commented that subsp. praetermissa does not reach the Arctic in the Urals.
Leymus ajanensis (V.N. Vassil.) Tzvelev. – Name applied differently. – Soreng et al. (2003) reported L. ajanensis to reach the Arctic in western Alaska as they synonymized it with L. interior. We consider L. interior apart from the more southern (not arctic) L. ajanensis. The Alaskan records (of L. ajanensis or L. interior) are not confirmed but L. interior reaches the Arctic in northeastern Asia.
Poa x herjedalica Harry Sm. (P. alpina x P. pratensis subsp. alpigena). – Not confirmed as a taxon. – Many Nordic authors have accepted P. x herjedalica as a taxon (e.g., Hylander 1953b; Mossberg et al. 1992; Elven 1994; Elven et al. 2005). It reaches the Arctic in mainland Norway and is reported from Svalbard. The plants (populations) seem to be mainly recent and very polyphyletic hybrids reproducing by bulbils (see, e.g., Åkerberg 1942 for cytology). Occurrence in Svalbard is dubious, not least because P. alpina there is almost exclusively bulbil-reproducing and unlikely to partake in hybridization.
Poa lindebergii Tzvelev (P. stricta Lindeb., non Roth nec D. Don). – Name misapplied. – Among the several proposed Scandinavian races of P. arctica is P. arctica subsp. stricta (Lindeb.) Nannf., based on P. stricta Lindeb. Tzvelev (1964b) recombined P. stricta Lindeb. as a variety of his P. tolmatchewii, indicating that he considered it a bulbil-reproducing parallel to the seed-reproducing P. arctica subsp. caespitans. He subsequently coined the species name P. lindebergii Tzvelev because the name P. stricta Lindeb. is inapplicable at rank of species due to homonymy. Tzvelev (1976, PAF proposal) reported it to reach the Arctic in Severnaya Zemlya and Kharaulakh in Siberia and also indicated occurrence in, e.g., Svalbard.

Lindeberg's Poa stricta was described with type from central Norway. It is a distinct and fairly frequent plant within a very compact range of about 30 x 40 km in the Dovrefjell and Trollheimen mountains. Nordic authors have considered it a bulbil-reproducing segregate of P. arctica (e.g., Nannfeldt 1940; Hylander 1945, 1953b). Its most distinctive characters, the dense growth with both intravaginal and short extravaginal shoots, the narrow leaves, the bulbils, and the narrow panicle, are not shared by the other Scandinavian representatives of P. arctica s. lat. and almost all features of assumed importance distinguish it from P. arctica subsp. caespitans (Tzvelev's proposed affinity). The narrow panicle is, however, modificative. This taxon is mostly found in late and wet (irrigated) snowbed sites. However, when it grows on low-lying river banks or road verges, the panicle becomes spreading (and large) and the tussocky growth less evident. Some years ago, some initial isoenzyme study was performed (Nordal and Philipp unpubl.), testing a possible hybrid origin of P. stricta Lindeb. from the seed-reproducing P. arctica var./subsp. elongata (the most frequent local race of P. arctica) and P. glauca or P. flexuosa, without much luck.

Soreng (in comment) proposed P. lindebergii to be the same as the arctic P. pratensis subsp. colpodea. Soreng et al. (2003) synonymized the two names. This assumption is supported by some morphological features, and the plants under these names have in common the comparatively low ploidy level. The reported chromosome numbers are mostly 2n = 35–42 in arctic subsp. colpodea and 2n = 38 and 39 in P. lindebergii (Nannfeldt 1940; Nygren 1950a, 1950b; Vestre in Engelskjøn 1979), whereas P. arctica subsp. elongata (Blytt) Nannf. in Norway has 2n = 70–76 (five populations), subsp. depauperata (Fr.) Nannf. in Norway 2n = 75–79 (five populations), and subsp. cespitans in Svalbard has 2n = 56 (two populations), see Engelskjøn (1979). However, in some other features the central Norwegian plants differ from the arctic ones, not least in the main character separating the P. arctica and P. pratensis complexes: narrow lemmas with rather straight hairs on veins and short hairs between veins in P. lindebergii as in P. arctica s. lat. vs. broad lemmas with strongly curly hairs on the veins and smooth between the veins in subsp. colpodea as in P. pratensis s. lat. We reject Soreng's synonymization (and Soreng now agrees with this, comment in 2008), but it does not influence the Checklist as P. lindebergii (or perhaps P. arctica subsp. stricta) in our opinion still is restricted to the small range in the decidedly not arctic central Norwegian mountains. The name P. stricta or P. arctica var./subsp. stricta has, however, been extensively misapplied in, e.g., Svalbard for P. pratensis subsp. colpodea.

We have found bulbil reproduction in arctic populations otherwise resembling P. arctica subsp. caespitans. Tzvelev's arctic reports may refer to such or related plants. They differ in several characters from P. lindebergii and might better be considered, until we know more, a bulbil-reproducing form within the P. arctica complex.

Poa nascopieana Polunin. – Not a taxon. – Aiken: This taxon should not be recognized. It was named for the Hudson Bay Co. vessel 'Nascopie'. The original description was based on a single collection (BM) from Pangnirtung in Baffin Island, that had peculiar bracts subtending the branches (Polunin 1940: plate II). This phenomenon he had observed in specimens of doubtful affinity in Colorado. Porsild (1957) mapped a second specimen (CAN) from Clyde Fiord in Baffin Island. R.J. Soreng in 1990 annotated the latter specimen as P. glauca. He has suggested that the type specimen may be abnormal possibly due to nematode infection (personal communication 1996). No other specimens that might be assigned to this taxon have been collected. Soreng et al. (2003): "The spikelets are mutated due to infection, and the characters of the plant do not allow certain identification".

Poa tolmatchewii Roshev. – Not confirmed as a taxon. – Tzvelev (1976) intended P. tolmatchewii as a name at species rank for the otherwise North American and North Atlantic P. arctica subsp. cespitans. However, as he specified it with a type from Taimyr in Siberia (Tzvelev 1976: 455), it is an independent name (and there is a much older species name available for subsp. caespitans, see the main text). Tzvelev reported P. tolmatchewii from the Arctic in Siberia and the Russian Far East. The synonymization of P. tolmatchewii with P. arctica subsp. caespitans is not supported by morphology (Haugen 2000). Tzvelev's hypothesis that the Russian plants are "undoubtedly hybridogeneous (or even a modern hybrid; P. arctica x glauca)" may well be true based on his chosen type but is probably irrelevant for P. arctica subsp. caespitans. As such a hybrid, it is not accepted for entry in the Checklist.

Puccinellia capillaris (Lilj.) Jansen (incl. P. pulvinata (Fr.) Tzvelev). – Probably not arctic. – Tzvelev (PAF proposal) accepted three species of the P. capillaris group from the Arctic in European Russia: P. capillaris, P. coarctata, and P. pulvinata. These three are considered closely related or identical in more recent western European literature but we consider P. capillaris and P. coarctata as two species. The western European P. capillaris is largely replaced by P. coarctata in northern Norway, northern Iceland, and almost certainly also in arctic Russia. Puccinellia capillaris reaches the fjord areas in northern Norway and the Murman area but we have not yet confirmed records from the arctic coasts. We consider P. pulvinata conspecific with P. capillaris but the Russian plant reported under this name probably belong to P. coarctata.


Aconogonon alpinum (All.) Schur. – Not arctic. – Petrovsky (1966) reported A. alpinum from the lower Jenisei River. Tzvelev commented that it probably does not reach the Arctic. Kashina and Tupitsina (1992) reported it only northwards to boreal Putorana.
Aconogonon sibiricum (Laxm.) H. Hara. – Not arctic. – Petrovsky (1966) reported A. sibiricum from the lower Jenisei River. Tzvelev commented that it probably does not reach the Arctic. Kashina and Tupitsina (1992) did not include this taxon or name.
Bistorta officinalis Delarbre (Polygonum bistorta L., Bistorta major Gray). – Name applied differently. – We consider the northern plants specifically distinct from the temperate–alpine European B. officinalis (see the B. officinalis aggregate in the main text).
Polygonum fowleri B.L. Rob. – Misidentified. – Hultén (1968a) mapped P. fowleri from the southwestern shores of Hudson Bay. Scoggan (1978c) reported P. fowleri only from the James Bay area, south of our Arctic, and included the more northern plant in P. boreale. Hinds (1995) transferred the record to P. hudsonianum. Polygonum fowleri occurs in southern Alaska but does not seem to reach the Arctic there either.
Polygonum oxyspermum C.A. Mey. & Bunge. – Misidentified. – Petrovsky (1966) reported P. oxyspermum from the lower Jenisei River but probably outside the Arctic. The record is certainly based on misidentification. The species is, as far as known, restricted to the decidedly not arctic Baltic and Kattegat–Skagerrak coasts.
Rumex alpestris Jacq. (R. acetosa L. subsp. alpestris (Jacq.) Á. Löve). – Name misapplied. – This name has been used very frequently for the montane–alpine R. arifolius and R. lapponicus but belongs, according to Pestova (1998), to the entirely different southern European alpine species R. scutatus L.


Potamogeton obtusifolius Mert. & W.D.J. Koch. – Not arctic. – Tzvelev (PAF proposal) reported P. obtusifolius to reach the Arctic in Canada. Porsild and Cody (1980) and Haynes and Hellquist (2000c) mapped no arctic occurrences.
Potamogeton strictifolius A. Benn. – Not arctic, and misidentified. – Porsild and Cody (1980) mapped P. strictifolius well into the Arctic in northwestern and north-central Canada. McJannet et al. (1993) mapped it from arctic localities in and to the east of the Mackenzie River Delta and from the southwestern corner of Hudson Bay. Haynes and Hellquist (2000c) excluded all these reports from the northern regions. They stated that "many specimens of this species have been misidentified as other species and vice versa".
Stuckenia striata (Ruiz & Pav.) Holub. – Not arctic. – Tzvelev (PAF proposal) reported S. striata to reach the Arctic in the Hudson Bay area (as Potamogeton latior Holub). Haynes and Hellquist (2000c) mapped S. striata with a much more southern range, northwards only to Oregon and Idaho.


Androsace chamaejasme Wulfen subsp. lehmanniana (Spreng.) Hultén. – Name probably misapplied. – Most American sources until now have applied this name to the major arctic race of A. chamaejasme. The name 'lehmanniana' is probably based on plants from the Caucasus and on a type that may have been destroyed. The arctic plants should be considered a separate subspecies for which subsp. andersonii seems to be the priority name. See the main text for more details.
Dodecatheon pulchellum (Raf.) Merr. subsp. pauciflorum (Durand) Hultén. – Not arctic. – Hultén (1968a) reported this plant from the lower Mackenzie River in the Northwest Territories, Porsild and Cody (1980) from the Porcupine River in northeastern Alaska (but not from the Mackenzie River). The species approaches but localities in the Arctic or the Borderline Arctic are not yet documented.
Primula cortusoides L. – Probably an erroneous record. – Kovtonyuk (1997: 42) reported this species to reach the Arctic in Taimyr. This may be a misprint for this southern European and central Asian species.
Primula cuneifolia Ledeb. subsp. cuneifolia. – Misidentified. – Hultén (1968a) mapped subsp. cuneifolia from the Seward Peninsula in western Alaska. Kelso (in comment) rejected this record as based on misidentified subsp. saxifragifolia.
Primula farinosa L. – Name misapplied. – Korobkov (PAF proposal) and many other sources have accepted P. farinosa from the Arctic in northeastern European Russia. The Russian material referred to it belongs to P. stricta (see Hultgård 1993), differing from P. farinosa in being homostylous as are also the arctic Russian plants. The reported Russian chromosome count of 2n = 18 (Zhukova et al. 1973), typical of P. farinosa but not of P. stricta, stems from boreal Siberia where true P. farinosa occurs.
Primula scandinavica Bruun. – Misidentified. – Scandinavian authors have several times reported P. scandinavica to reach the Arctic in northeastern European Russia. These records are probably the same as those reported for P. farinosa (see above) by Russian authors and seem to belong to P. stricta. Primula scandinavica is a Scandinavian species that reaches north to Tromsø in Norway but which does not approach the Arctic.


Aconitum delphinifolium DC. subsp. chamissonianum (Rchb.) Hultén. – Misidentified. – Yurtsev (in comment) reported subsp. chamissonianum from localities in the Seward Peninsula in western Alaska, together with subsp. delphinifolium. Murray and Elven have inspected the relevant specimens (ALA). They do not accept Yurtsev's interpretation of them but see them rather as part of the variation within populations of subsp. delphinifolium.
Anemone narcissiflora L. – Name applied differently. – We consider the northern and arctic representatives of this group as several separate species, all different from the central and southern European A. narcissiflora s. str.
Leptopyrum fumarioides (L.) Rchb. – Not arctic. – Löve and Löve (1975a) reported this species to reach the Arctic in Siberia. We can find no indication whatsoever that it reaches or approaches the Arctic as defined by us (or by the Löves).
Ranunculus altaicus Laxm. – Name misapplied. – This name has sometimes been applied to the northern plant more commonly known as R. sulphureus Sol. Ranunculus altaicus is a much more southern, diploid species (see R. sulphureus in the main text).
Ranunculus borealis Trautv. – Name applied differently. – The majority of treatments of the floras of Eurasia have applied the name R. borealis to a fairly widespread northern plant. Tzvelev (1994, in comment) has shown that the northern plant differs from the southern Siberian one to which the name R. borealis belongs. The northern plant is therefore now renamed as R. subborealis.
Ranunculus flammula L. – Name applied differently. – Several North American authors (e.g., Whittemore 1997) have applied this name to what we consider R. reptans. In the European and type meaning, R. flammula is an oceanic, western European species that does not reach the Arctic.
Ranunculus pedatifidus Sm. – Name applied differently. – The name is based on an Altai plant but has been very widely applied until recently to a common arctic plant. We consider this plant R. arcticus (R. affinis).
Ranunculus polyanthemos L. – Probably not arctic, or possibly misidentified. – Tolmachev (1971b) reported R. polyanthemos to reach the Arctic in, e.g., the Timanskaya Tundra and the Pechora River estuary in European Russia. Martinenko (1976b) and Jalas and Suominen (1989) mapped it from the Arctic in northeastern European Russia. Rebristaya commented that the species is not arctic and should be excluded from the Checklist. We do not know whether this comment relates to the identification of the Russian material or to a consideration of the location of the reported plants. We should note that the most evident diagnostic feature, the patent hairs on stems and petioles, is in common with a species certainly present in these areas: R. subborealis. In northwestern Europe, R. polyanthemos is thermophilous and only found well south of the Arctic.
Ranunculus scandinavicus N.I. Orlova. – Name misapplied. – Orlova (1956) mapped this species to reach the Arctic in the Murman area, including the Rybachi Peninsula. However, Orlova stated her name (R. scandinavicus N.I. Orlova, Fl. Murmansk. Obl. 3: 288, 1956; R. acris subsp. scandinavicus (N.I. Orlova) Á. Löve & D. Löve, Bot. Not. 128: 512, 1976) to be a nomen novum for R. sylvaticus Fr., Novit. Fl. Svec. Mant. 3: 50 (1842), non Thuill., Fl. Env. Paris, ed. 2: 276 (1799), without a separate description or type. Fries' R. sylvaticus is now considered synonymous with a much more southern race of R. acris – subsp. friesianus (Jord.) Syme – adventive in southern and eastern Fennoscandia. Orlova's name R. scandinavicus is therefore a synonym for R. acris subsp. friesianus (see Casual taxa). It is improbable that Orlova's Murman area records are based on such adventive, quite thermophilous plants. It is more probable that they refer to plants of R. subborealis subsp. subborealis. Ranunculus acris subsp. friesianus and R. subborealis share the patent hairs on stems and petioles but differ in other characters (e.g., rhizome structure and leaf dissection). Orlova's informal description points towards R. subborealis.


Alchemilla obtusa Buser. – Name misapplied. – Alchemilla obtusa is reported to reach the Arctic in European Russia (e.g., Sekretareva 1999; Tikhomirov PAF proposal). Already Fröhner (1964, 1995) re-evaluated the northern plants as A. samuelssonii. Alchemilla obtusa s. str. is central European.
Alchemilla oxyodonta (Buser) C.G. Westerl. – Name misapplied. – In its type meaning, A. oxyodonta is a local agamospecies in central Scandinavia. This name has, however, been applied much more widely to parts of what has been denoted as the A. acutidens aggregate, e.g., in arctic European Russia as late as by Sekretareva (1999, 2004). These Russian plants rather belong to A. norvegica or related species.
Alchemilla transpolaris Juz. – Not arctic. – Alchemilla transpolaris is an insufficiently known agamospecies of the Murman area. Occurrence in the Arctic is not confirmed. Tikhomirov (PAF proposal) did not include it, neither as accepted species nor as synonym.
Alchemilla vulgaris L. – Name misapplied. – Fröhner (1986) identified Linnaeus' A. vulgaris with A. acutiloba and considered the former the priority name for this species (see A. acutiloba in the main text). Fröhner's lectotype was based on an inadmissible element and must be rejected (Kurtto et al. 2007; Jarvis 2007). The name A. vulgaris is therefore still without a specific meaning.
Chamaerhodos erecta (L.) Bunge. – Not arctic. – Yurtsev (1984d) reported C. erecta to reach the Arctic in Siberia. Siberian sources do not report it so far north.
Cotoneaster cinnabarinus Juz. – Not arctic. – Sekretareva (1999) reported C. cinnabarinus to reach the Arctic in the Murman area (together with C. x antoninae). The northernmost occurrence in the Murman area seems to be situated south of the Arctic.
Cotoneaster uniflorus Bunge. – Name misapplied. – Many authors have reported C. uniflorus from the Arctic in Polar Ural and surroundings. Fryer and Hylmö (2009) assigned the arctic plants to C. uralensis B. Hylmö & J. Fryer and reserved the name C. uniflorus for a non-arctic Siberian plant. Cotoneaster uniflorus is a sexual diploid (2n = 34, Gladkova in Fedorov 1969; Krasnoborov et al. 1980), whereas C. uralensis is apomictic (Fryer and Hylmö 2009) and probably polyploid.
Potentilla diversifolia Lehm. – Name misapplied. – This name has been used for a disjunct Cordilleran and northeastern North American species including the Greenlandic P. ranunculus. Soják (1996) typified the name P. diversifolia on a hybrid P. glaucophylla x hippieana. The plant to which the name P. diversifolia has been applied is P. glaucophylla.
Potentilla hookeriana Lehm. – Name misapplied. – The name P. hookeriana has frequently been applied to what we consider P. arenosa. According to Soják, P. hookeriana is a later synonym for P. rubricaulis Lehm. Ertter (in Ertter et al. 2011) has rather identified the type with a taxon restricted to the more southern Rocky Mts.
Potentilla multifida L. – Name misapplied. – Potentilla multifida is a non-arctic eastern European species (Soják 2005). The name has been extensively applied to several other northern plants (e.g., by Hultén 1968a; Porsild and Cody 1980) now accepted as different species.
Potentilla virgulata A. Nelson. – Name misapplied. – The name P. virgulata has been much applied (e.g., by Hultén 1968a) to a northwestern North American plant. Ertter et al. (2011) consider P. virgulata a much more southern plant and the northern plant as P. litoralis Rydb.
Rosa woodsii Lindl. – Not arctic. – Hultén (1968a) mapped R. woodsii to reach very close to the Arctic in three places in Canada near the southern side of Hudson Bay and James Bay. Scoggan (1978c) only accepted localities well south of the Arctic.
Rubus stellatus var. decipiens Gladkova. – Not a taxon. – Varietas decipiens is most probably a hybrid swarm between R. arcticus s. str. and R. stellatus.
Sieversia pusilla (Gaertn. ex Steud.) F. Bolle. – Not arctic. – Löve and Löve (1975a) reported S. pusilla to reach the Arctic in northeastern Asia. Yakubov and Nedolushko (1996) only mapped occurrences on the Koryak coast south of the Arctic in South Chukotka.
Sorbus aucuparia L. subsp. praemorsa (Guss.) Nyman. – Name misapplied. – Löve and Löve (1975a) reported subsp. praemorsa to reach the Arctic in the Russian Far East. This subspecies was described from and is otherwise considered restricted to the Mediterranean region (see Warburg and Kárpáti 1968). We have no idea what the Löves can have meant when they applied this name to a northeastern Asian plant.
Spiraea beauverdiana C.K. Schneid. – Name misapplied. – This name was uniformly applied to the most widespread amphi-Pacific/Beringian Spiraea until Uttal (1973) showed that it belongs to a much more southern plant. The arctic plant is S. stevenii.


Galium davuricum Turcz. ex Ledeb. – Probably not arctic. – Tzvelev (1987d) reported G. davuricum from "Arctic Yakutia" (Kharaulakh). Naumova (1996) did not map it from northern Yakutia and Sekretareva (1999) did not include it as arctic.
Galium wirtgenii F.W. Schultz. – Not arctic, and name probably misapplied. – Galium wirtgenii belongs to the G. verum group and was reported by Tzvelev (1987d) from northern Siberia. It does not seem to reach the Arctic and its occurrence east of central Europe is disputed. Tzvelev's application of the name does not conform to the European one.


Salix athabascensis Raup. – Probably not arctic. – Argus (2007) mapped this northwestern North American species east to the southwestern shore of Hudson Bay. It may be a borderline case. In the west he mapped it into the non-arctic parts of the Mackenzie Mountains in the Northwest Territories and to northeastern Alaska.
Salix commutata Bebb. – Probably not arctic. – Argus (2007) mapped this western North American species north to southwestern Alaska, close to the (somewhat arbitrary) arctic boundary. It may be a borderline case.
Salix dasyclados Wimm. – Name misapplied. – The name S. dasyclados is now typified on Polish material (Larsson 1995: 343), possibly of garden hybrid origin, and outside the known range of the native species to which the name has been applied in a northern and arctic context. That species is now treated as S. burjatica.
Salix discolor Muhl. – Not arctic. – Lavoie and Morisset (1987) reported S. discolor from Fort Chimo in Quebec, an arctic locality. Argus commented that it is not documented from the Arctic in Quebec or elsewhere.
Salix lasiandra Benth. (S. lucida Muhl. subsp. lasiandra (Benth.) E. Murray). – Not arctic. – Hultén (1968a) and Argus (2007) mapped S. lasiandra to reach west to the Yukon River Delta in western Alaska. The westernmost locality reported (Holy Cross, leg. Palmer and Miller 1257, ALA) is, however, still outside the Arctic.
Salix lucida Muhl. – Probably not arctic. – Argus (2007) mapped this eastern North American species to almost reach the Hudson Bay on the southwestern (Manitoba), southern (Ontario), and southeastern shore (Quebec). It may well be a borderline case.
Salix maccalliana Rowlee. – Probably not arctic. – Porsild and Cody (1980) mapped S. maccalliana north to Hudson Bay. The locality (near York Factory) is, according to Argus, south of the Arctic. However, Argus (2007) mapped it to reach Hudson Bay also east of the entrance to James Bay (Pointe Louis-XIV). It may well be a borderline case.
Salix myricoides Muhl. – Not arctic. – Salix myricoides is stated by several sources to reach the Arctic along the eastern shore of Hudson Bay in Quebec. Argus has not been able to confirm these occurrences by specimens.
Salix petiolaris Smith. – Perhaps not arctic. – Argus (2007) mapped this nearly trans-American species from an isolated site at Pointe Louis-XIV on Hudson Bay east of the entrance to James Bay (Quebec). The site may be in the Borderline Arctic.
Salix pyrifolia Andersson. – Not arctic. – Several sources suggest S. pyrifolia to reach the Arctic in northeastern Canada. However, the relevant occurrence (Quebec: Richmond Gulf) is not arctic. It also approaches the Arctic in the northern Yukon Territory (Argus 2007).
Salix setchelliana C.R. Ball. – Erroneous record. – Hultén (1968a) mapped S. setchelliana from northern Alaska but Cody (1996) and Argus (in comment) rejected the record.
Salix stolonifera Coville. – Probably misidentified. – This species is related to S. ovalifolia. Argus commented that S. stolonifera (subsp. stolonifera) is barely reported from the Arctic at Cape Pierce in southwestern Alaska. The report is based on collections by L. Dick (CAN), two of which have been reidentified as S. arctica.


Sarracenia purpurea L. – Not arctic. – This unmistakeable species approaches the Arctic at the southern side of Hudson Bay but seems to keep some distance from the boundary everywhere, according to Scoggan (1978c) and the map in Porsild and Cody (1980).


Micranthes x jamalensis (Zhmylev & Razzhivin). – Not confirmed as a taxon. – Zhmylev (PAF proposal) assumed M. x jamalensis to be an Asian hybrid species probably developed from M. nelsoniana subsp. aestivalis x M. nivalis (or M. hieracifolia). It was reported with a chromosome number of 2n = 70 (source not given). The same doubts are relevant here as for many other proposed hybrid species. We need additional evidence before it can be accepted as more than occasional or ecotonal hybrids.
Micranthes jurtzevii (Zhmylev). – Not confirmed as a taxon. – Zhmylev (PAF proposal) accepted M. jurtzevii as an Asian species with certainty known only from Novaya Zemlya. This plant is not clear as to morphological distinction, relationships, and geographical range. It is not accepted until more information is available.
Micranthes pacifica (Hultén). – Not arctic. – Zhmylev (PAF proposal) reported M. pacifica to reach the Arctic in Alaska. It seems to stop south of the Arctic in the Kuskokwim Mountains.
Micranthes x tolmatchevii (Zhmylev). – Not confirmed as a taxon. – Zhmylev (PAF proposal) accepted M. x tolmatchevii as an "arctic Chukotkan species, which was probably formed as a result of hybridization between M. porsildiana and M. nelsoniana subsp. nelsoniana in their ecological contact zone (margins of snowbeds)". It is reported from East and South Chukotka, in both regions as rare. The question is whether it should be considered just a hybrid (between two assumedly closely related species, by Brouillet 2008 treated as two varieties of one species) or accepted as an independent taxon. Its occurrence in an ecotone points towards the former.
Micranthes x ursina (Sipliv.). – Not confirmed as a taxon. – Zhmylev (PAF proposal) accepted M. x ursina as a hybrid species from M. hieraciifolia x M. nivalis. According to him, it is known with certainty only from the Chetyrehstolbovoy Island (Medvezhyi Archipelago) in the Yana–Kolyma region of northern Siberia, with holotype (LE): "Archipelago Insulae Ursinae, ins. Czetyrechstolbovoj, prope stationem polarem", 06. July 1952, leg. A. Danilov. Zhmylev reported it also from Novaya Zemlya where Rebristaya (1984) mapped it from three localities, and with a question mark from Svalbard. The Svalbard plants reported as this hybrid are misidentified as are similar Scandinavian 'hybrids'. We cannot exclude the possibility of hybrids between these parents. However, before acceptance of a hybrid species it must be documented to have an independent reproduction and preferrably a consistent range, and it must be experimentally confirmed in light of the proven misinterpretations and misidentifications in other regions.
Saxifraga flagellaris Willd. – Name applied differently. – This name in its strict meaning belongs to a Caucasian plant. It has been widely applied in the Arctic until recently, especially in North America. The arctic plants are currently considered two species – S. platysepala and S. setigera – both well different from the Caucasian S. flagellaris s. str.
Saxifraga hirculus L. subsp. alpina (Engl.) Á. Löve. – Name misapplied. – Löve applied subsp. alpina as the priority name for the tetraploid arctic European plants of S. hirculus s. lat. (Löve 1970a, 1970b; Löve and Löve 1975a etc.), whereas he assigned the diploids to subsp. propinqua (as did Hedberg 1992). This resulted in the following dry British comment from Webb and Gornall (1989): "Icelandic plants have been distinguished as subsp. alpina ... but the fact that the type of this taxon comes from Sikkim does not inspire confidence, and in any case the distinctive charactes are only of varietal value." These authors, however, kept the case open (p. 271) for acceptance of subsp. propinqua. Hedberg (1992) included the earlier name S. hirculus subsp. alpina (Engl.) Á. Löve 1970 among the synonyms of his subsp. compacta Hedberg 1992 but this probably reflects applications of names rather than validity. Hedberg did not map this taxon from the original region (Sikkim) of Engler's var. alpina.


Myricaria germanica (L.) Desv. – Not arctic. – Myricaria germanica reaches far north in Porsanger and Lebesby in Norway but does not fully reach the Borderline Arctic.


Daphne mezereum L. – Not arctic. – Daphne mezereum reaches far north in the Murman area, the Kanin Peninsula, and the Malozemelskaya and Bolshezemelskaya tundras in European Russia. However, all the mapped localities seem to be too far south to be in the Borderline Arctic.


Urtica angustifolia Fisch ex Hornem. – Not arctic. – Tolmachev (1966c) reported U. angustifolia from the lower Kolyma River in Siberia or West Chukotka and from the Anadyr River basin in South Chukotka. Geltman (1992) mapped it close to the Arctic in northeastern Siberia but not close enough to be in the Borderline Arctic. Geltman (1991) mapped it only from the non-arctic parts of the Anadyr drainage.


Viola achyrophora Greene. – Not confirmed as a taxon. – Viola achyrophora was described from western Alaska with holotype (CAN): the Pribilof Islands, St. Paul Island, 18. July 1897, leg. Macoun. Hultén (1947: 1130) accepted it with some doubts and mapped it throughout the Bering Strait area (many arctic localities). Later, Hultén (1968a) included it in the synonymy of V. epipsila subsp. repens. The species was, however, accepted by Sorsa (1968) and reported with 2n = 24 (same as V. epipsila). This group may include some unresolved taxa. Our exclusion from the Checklist is mainly due to lack of information.
Viola microceras Rupr. – Not confirmed as a taxon. – The recognition of V. nicroceras is based on the following holotype (LE): European Russia: "Insula Kolgujev interior", 1843, leg. F.J. Ruprecht. According to Tzvelev (1996a), this is a local species of the island of Kolguev. The only collection found in LE is the type, which obviously is the basis of Ruprecht's illustration. It differs from 'normal' V. biflora in leaves distinctly concentrated in a rosette and in small, elegant flowers with narrow petals. The plant is characteristic and differs visually much from V. biflora. However, one specimen is too little to base a taxon on. We (Tzvelev and Elven) therefore decide, for the time being, to relegate the question to this comment.
Viola montana L. (V. canina subsp. montana (L.) Hartm.). – Name misapplied. – Viola montana L., Sp. Pl.: 935 (1753), was described from "Alpibus Lapponiæ, Austriæ, Baldo [Monte Baldo in Italy]" and obviously intended as a mountain plant. According to Nikitin (1988, 1995), the specimen(s) available as possible types of the name belong to the decidedly non-arctic V. elatior Fr., and at least two of the literary sources that Linnaeus (1753) cited are more southern European. The majority of previous floristic treatments have, however, applied the name for a species closely related to V. canona or a subspecies of that species. Even in this meaning, V. montana seems very difficult to characterize as a taxon (Marcussen 2007, 2010).
Viola palustroides (W. Becker) Tzvelev (V. epipsila subsp. palustroides W. Becker). – Probably misidentified. – In an arctic context, V. palustroides has only been reported as sterile plants from one geothermal site in East Chukotka. The identity is dubious.
Viola rupestris F.W. Schmidt subsp. relicta Jalas. – Misidentified. – Subspecies relicta has been recorded north to the Arctic in Nordkapp in Finnmark, Norway (e.g., Elven et al. 2005). The material from the northernmost localities has recently been re-identified as V. canina. The current northern limit for subsp. relicta is in Porsanger south of the Arctic.


Gymnocarpium disjunctum (Rupr.) Ching. – Misidentified. – McJannet et al. (1993) mapped G. disjunctum from the Arctic on islands in the Hudson Bay and from Ungava. Pryer (1993) restricted G. disjunctum to non-arctic western North America and the Russian Far East and mapped all eastern North American plants as G. dryopteris.
Gymnocarpium robertianum (Hoffm.) Newm. – Misidentified. – Reports of G. robertianum from the Arctic in northwestern North America (e.g., Hultén 1968a, Porsild and Cody 1980) are based on misidentified G. continentale and the hybrid G. continentale x dryopteris (G. x intermedium). The species is amphi-Atlantic and approaches the Arctic in the Ungava Bay area in eastern Canada, according to Pryer (1993), but seems too southern to merit inclusion as a borderline case.

6  Taxonomic treatment

The Checklist follows a traditional taxonomic arrangement of the three main groups: pteridophytes (families 1–12), gymnosperms (families 13–14), and angiosperms (families 15–91). Angiosperm families are circumscribed and grouped according to the orders accepted by APG2 (Stevens 2001 onwards), except that we keep Papaveraceae and Fumariaceae apart and that we include the order Boraginales (family 83, Boraginaceae). Genera are arranged in some proposed taxonomic order within families and species within genera. This has been chosen instead of an alphabetic order because there often is need for notes on a group of genera, and very often for notes on a group of species.

Taxa that we accept (fully or provisionally) are enumerated consecutively with one number for families (e.g, 42 Caryophyllaceae), one for genera (e.g., 4201 Stellaria), one for species (e.g., 420118 Stellaria ruscifolia), and with letters for races (e.g. 420118a Stellaria ruscifolia subsp. aleutica). Agamospecies in the larger complexes of Hieracium s. str., Taraxacum, and the Ranunculus auricomus groups are not enumerated.

The information for species and races is summarized under four items:

  1. Nomenclature and type(s)
  2. Chromosome numbers and ploidy levels
  3. Phytogeographical pattern and distribution in countries (for Russia in three separate parts)
  4. Notes

6.1  Nomenclature and type(s)

Nomenclature. The information items on nomenclature given for genera, species, and races are: the name accepted for the Checklist, its basionym if relevant, and synonyms. As synonyms we consider only names accepted in major sources (see below). Names are given with authors and publication data. Authors are abbreviated according to Brummitt and Powell (1992) followed by IPNI (the International Plant Name Index, or the principles applied therein. Books and comparable works are abbreviated according to Stafleu and Cowan (1976–1988) or the principles applied therein. Periodicals are abbreviated according to Bridgson (2004 Botanico-Periodicum-Huntianum, ed. 2) or the principles applied therein (but with one or two exceptions you may be lucky enough to find).

Our accepted name is the priority name that in our opinion best reflects the rank we find appropriate for the taxon in question. This is the name and the rank that we propose for Panarctic use.

By synonyms we mean names that we consider as representing the same taxon. Homotypic names (based on the same type) are joined in paragraphs, whereas heterotypic names (based on different types) are separated as paragraphs. Names that we are not certain are synonyms are marked with a question mark.

The synonymy of some arctic plants is extensive as the same plant may have been described several times in different regions, and as the views of their rank often have varied. A full synonymy is not intended in the Checklist. What we have aimed for is to include the names accepted in the more recent major floristic surveys of the Arctic in general and of the single countries and major regions. These standard sources include the more recent standard Floras for the major (usually national) areas, and in addition some more general sources. We have accepted names from recent revisions and monographs and have allowed for some additional names on special justification. We have tried to evaluate each of the names, whether they represent separate taxa or belong in the synonymy of others.

The applied standard sources (more bibliographic data in the references):

General sources

Hultén, E. 1958. The amphi-atlantic plants.
Hultén, E. 1962, 1971a. The circumpolar plants, I–II.
Hultén, E. and Fries, M. 1986. Atlas of North European vascular plants, I–III.
Löve, Á. and Löve, D. 1975a. Cytotaxonomical atlas of the arctic flora.


Tolmachev, A.I. and Yurtsev, B.A. (eds.) 1960–1987. Flora arctica URSS, I–X.
Fedorov, A.A. (ed.) 1974–. Flora partis europaeae URSS. I–, and its continuation in Flora europaeae orientalis. Volumes appearing after Flora arctica URSS are taken into account.
Tolmachev, A.I. (ed.) 1974–1977. Flora regionis boreali-orientalis territoriae europaeae URSS, I–IV.
Kharkevicz, S.S. (ed.) 1985–1996. Plantae vasculares Orientis Extremi Sovietici, 1–8.
Krasnoborov, I.M. et al. (eds.) 1988–1997. Flora Sibiri, 1–14.
Sekretareva, N.A. 1999. The vascular plants of the Russian Arctic and adjacent territories.
Sekretareva, N.A. 2004. Sosudistie rasteniya Rossiiskoi Arktiki i sopredelnikh territorii.

North America (including Greenland)

Flora of North America Editorial Committee (eds.) 1993 onwards. (Volumes 1–5, 7–8, 19–26).


Anderson, J.P. 1959. Flora of Alaska and adjacent parts of Canada.
Hultén, E. 1968a. Flora of Alaska and neighboring territories.
Welsh, S.L. 1974. Anderson’s Flora of Alaska and adjacent parts of Canada. – This work applies subspecific categories differently from the Checklist. Species names applied are included among synonyms but not varietal names.


Porsild, A.E. 1964. Illustrated flora of the Canadian Arctic Archipelago (Ed. 2).
Porsild, A.E. and Cody, W.J. 1980. Vascular plants of Continental Northwest Territories, Canada.
Cody, W.J. 1996, 2000. Flora of the Yukon Territory. Eds. 1 and 2.
Aiken, S.G. et al. 2007. Flora of the Canadian Arctic Archipelago.

In addition we have used, but not excerpted systematically, recent local floras and flora drafts for northern parts of Manitoba, Ontario, Quebec, and Labrador – Newfoundland.

Note that Scoggan, H.J. 1978–1979, The Flora of Canada, I–IV, is not included among our standard sources.


Böcher, T.W. et al. 1978. Grønlands flora (Ed. 3).
Feilberg, J. 1984a. A phytogeographical study of South Greenland. Vascular plants. – Meddel. Grønland, Biosci. 15: 1–70.
Bay, C. 1992. A phytogeographical study of the vascular plants of northern Greenland – north of 74 northern latitude. – Meddel. Grønland, Biosci. 36: 1–102.
Fredskild, B. 1996. A phytogeographical study of West Greenland between 6220’N and 74N. – Meddel. Grønland, Biosci. 45: 1–157.


Tutin, T.G. et al. (eds.) 1964–1980. Flora Europaea, I–V.
Tutin, T.G. et al. (eds.) 1993. Flora Europaea, I (Ed. 2).
Jalas, J. et al. (eds.) 1972 onwards. Atlas florae europaeae 1– (from pteridophytes to parts of Rosaceae completed).


Kristinsson, H. 2008.
Kristinsson, H. 2010. Internal note: Reference to be added!
In addition: Kristinsson’s unpublished list of plants found in the arctic parts of Iceland.

Note that we do not consider Löve 1970a, 1977, Íslenzk ferdaflóra, a standard source.

Norway (including Jan Mayen and Svalbard)

Elven, R. 1994. Lid’s Norsk flora (Ed. 6).
Elven, R. and Elvebakk, A. 1996. A catalogue of Svalbard plants, fungi, algae, and cyanobacteria. Part 1. Vascular plants.
Rønning, O.I. 1996. Svalbards flora (Ed. 3).
Jonsell, B. (ed.) 2000 onwards. Flora Nordica 1–.
Elven, R. et al. 2005. Lid’s Norsk flora (Ed. 7).

Types. The type defines the meaning of a name. The nomenclatural type of a name of a species or a race may be: (1) the single item, a herbarium voucher or an illustration, referred to by the original author of the name (the holotype); (2) an item selected later among those referred to or certainly inspected by the author (a lectotype selected among the original material); (3) or an item selected outside the original material (or if the original material is lost) but to confirm established usage or to specify the meaning of a name (a neotype or rarely an epitype when the original material may be ambiguous). There are also some other possibilities, all regulated by the International Code of Botanical Nomenclature (ICBN, currently the Vienna Code, McNeill et al. 2006).

Information about the types connected to the names in the Checklist (accepted names and synonyms) has been included to some extent, but we have made no systematic search for type information. Type identification is a major aspect of the production of a Flora but not of a Checklist. Type information is given with reference to the herbaria (abbreviated as in Index Herbariorum) where the vouchers are deposited (or works for illustrations), and with reference to where a designated lectotype, neotype, or epitype is published. Where we do not have type information available, we have mostly included some reference to the geographic region from where the plant in question was described. This is done because the geographic origin of a type may be of importance for the interpretation of the meaning of a name.

6.2  Chromosome numbers and ploidy levels

Chromosome numbers and ploidy levels are often important for interpretation of arctic plants, due to the documented high levels of polyploidy in arctic floras. We have therefore (after some initial discussions) decided to summarize the reports of chromosome counts from northern areas, for the plants included in the Checklist. Many reports are referred after secondary sources (see below) but for some of the more important reports we have gone back to the primary sources. We also try to roughly indicate where the counted material was collected. Where there only are a single or a few reports we refer to the publications, whereas several reports mean 5–10, and numerous reports more than 10.

Initially in the Checklist process (in 1998), we decided to use Löve and Löve (1975a, Cytotaxonomical atlas of the arctic flora) as a baseline and only to search for and enter counts published later (and earlier counts omitted by the Löves). This decision has been revised as Löve and Löve (1975a) has proved to be an unreliable baseline. The Löves often changed the information in several ways from what was originally published. They omitted almost all counts that did not fit with their concept that: (a) each species – as a rule – should have one and only one chromosome number, and that (b) counts of different numbers belonged to different species. This concerns hundreds of the species included by Löve and Löve (1975a). In some cases they also 'corrected' (i.e., changed) the numbers from what was originally reported, probably to fit better with their concepts. Especially where the original counts were reported as a range, the Löves 'adjusted' this to a mean number fitting the prevalent known counts. The most serious objection to the Löves' Atlas is, however, that they transferred numerous reports from the taxon to which they were originally assigned to other taxa, following their concept (b) above, quite certainly without ever checking vouchers for the counts. In addition, the counts made by the Löves themselves often deviate from all other counts assigned to the same taxon, and there is very rarely vouchers available that can be inspected for the Löve counts. All this means that Löve and Löve (1975a) gave a much more regular impression of the chromosome number variation in arctic plants than the reality as expressed by the original reports. If a baseline is to be used, Fedorov (1969) is the more reliable compilation. We have abandoned Löve and Löve (1975a) as a baseline and made numerous notes in the text where there are discrepancies or where they almost certainly have 'corrected' (read: corrupted) data. This is the policy applied also by Flora Nordica (Jonsell 2000 onwards), where counts by the Löves have been decided omitted even if these authors are the major source of, e.g., chromosome counts of Icelandic plants. We have not gone that far for the Checklist as we include many primary reports by the Löves. However, for some of the most dubious publications by the Löves, we give a warning in each case where relevant (e.g., Löve 1954a, 1954b; Löve et al. 1957; D. Löve 1953, 1960) .

Our compilation is then mainly based on Fedorov (1969) for earlier counts and on the Regnum Vegetabile and Missouri Botanic Garden chromosome number lists (1965–2003), the lists published in Taxon (1964–1988), and the subsequent lists in IOPB Newsletters (1987 onwards). There is an overlap in time between Fedorov (1969) and the regular chromosome number lists that makes the survey comparatively comprehensive up to 2000. The records after this time are rather sketchy, which is deplorable as chromosome numbers still are a major source of biosystematic information and especially for polyploid evolution, in spite of all recently developed molecular markers.

In the last years, flow cytometry (FCM) has emerged as a rapid and inexpensive method for deciding ploidy levels, but not for deciding the exact chromosome number. Flow cytometry has been applied on several arctic plants. In the Checklist, reports of flow cytometry results are given as FCM ploidy level.

In the Checklist, the numbers are always reported as a somatic (mitotic) number ('2n ='), even if the original counts were made on meiotic cells. This is done for practical reasons, also because some of the secondary sources enter only somatic numbers. It may, however, be erroneous for some plants, especially for agamic plants with unreduced gametes. Numbers reported by several independent sources, or where we have checked the voucher specimens, are marked in bold. The chromosome voucher herbarium in St. Petersburg (LE) and the herbarium and database of the University of Alaska Fairbanks (ALA) are especially recommended for those who want to check vouchers of arctic chromosome counts. Some deviating counts (assumed aneuploids, and the results of endoploidy or occasional polyploidy within populations) are included as notes. We have referred to reports and numbers that we do not accept under the heading of 'Not included', with a justification.

Generally, the Checklist includes counts made in the Arctic and in adjacent boreal areas, which means that counts are considered from all of Alaska, most parts of Canada (and sometimes the northern U.S.A.), Greenland, Iceland (even if the Löves' counts are often dubious), the other Nordic countries, and northern and central parts of Russia (European Russia, Siberia, and the Russian Far East). For taxa where few counts are known, all counts (also more southern, temperate ones) are usually considered.

6.3  Phytogeographical pattern and distribution among countries

The presence and frequency in the biogeographic regions and bioclimatic zones are reported in the distribution table. In the main text is included only a general distribution pattern and a list of the nations (and main Russian regions) where the taxa are reported from the arctic parts, by the following abbreviations: ICE (Iceland), NOR (mainland Norway and the Norwegian arctic islands of Jan Mayen and Svalbard), RUS (European Russia east to and including Polar Ural and Novaya Zemlya), SIB (Siberia from the eastern margin of Polar Ural east to the Kolyma River), RFE (the Russian Far East), ALA (Alaska), CAN (Canada), and GRL (Greenland). There are two reasons for this inclusion of nations: partly that some of the biogeographic regions in the distribution table cover two nations (Ic = Iceland and Norwegian Jan Mayen, SF = Norwegian Svalbard and Russian Franz Joseph Land, FN = mainland Norway and mainland Russia, AN = Alaska and the Canadian Yukon Territory (and a very small part of the Northwest Territories), and EP = Canadian islands and northern Greenland), partly that many of the notes concern geography. Nations where the taxon in question only occurs in the Borderline Arctic are marked in parentheses as '(SIB)'. Adventive occurrences are marked with '*' as 'SIB*' when persistent, or with '**' as 'SIB**' when only casual. Note, however, that taxa with casual occurrence throughout the Arctic are excluded from the main treatment but included in a separate chapter above.

The general distribution patterns (assumed native ranges) are reported by use of the following geographical concepts:

American Atlantic: In coastal / oceanic parts of eastern North America and often southern Greenland.

American Beringian: Confined to the (mega)Beringian parts of northwestern North America, mainly Alaska and the Yukon Territory. We also include the Canadian coast some distance east of the Mackenzie River and parts of the western Canadian Arctic Archipelago assumed to have been little or not covered by the Pleistocene glaciations, i.e., the remnants of the assumed 'Pleistocene Shelf'.

American Pacific: In coastal / oceanic parts of western North America south of the Beringian areas.

American Pacific/Beringian: In both western coastal and northwestern Beringian parts of North America.

Amphi-Atlantic: On both sides of the North Atlantic, i.e., both in northeastern North America (and/or Greenland) and in mainland northwestern Europe (and/or Iceland and Svalbard). W denotes main occurrence west of the Atlantic, E main occurrence east of the Atlantic (including Iceland).

Amphi-Beringian: On both sides of the northernmost Pacific, the Bering Sea, and/or the Chukchi Sea; in northeastern Asia mainly east of the Kolyma River and the Verkhoyansk Mountains, in northwestern North America mainly west of the Mackenzie River, south to southern Alaska, the Aleutian Islands, and Kamtchatka. E denotes main occurrence in American Beringia, W main occurrence in Asian Beringia.

Amphi-Pacific: More or less temperate coastal on both sides of the North Pacific south of the Beringian regions. For E and W, see amphi-Beringian.

Amphi-Pacific/Beringian: On both sides of the North Pacific and the Chukchi Sea, both in the Beringian parts and farther south. For E and W, see amphi-Beringian.

Asian: East of the Urals, in a northern context mainly Siberia and the Russian Far East but many ranges extend to Turkey, the Caucasus, Iran, central Asia, Mongolia, northern China, Korea, and Japan. If there is no specification, the taxon is widespread in the Asian parts. C denotes southern Siberia and central Asia, mostly north of the Himalayas. C–E denotes these areas and in addition southern parts of the Far East. C–NE denotes ranges reaching in the mountains from southern Siberia and central Asia northeastwards to Chukotka. E denotes eastern parts of Siberia (sometimes south to China) and southern parts of the Far East. N/C denotes disjunct ranges with a gap between northern Siberia and southern Siberia / central Asia. N denotes northern parts of Siberia and may include northwestern Siberia and the northern Russian Far East. NE denotes temperate, boreal, and/or arctic eastern and northeastern Siberia (Yakutia) and the Russian Far East, sometimes extending south to the Lake Baikal area, northern Mongolia, northern China, Korea, and Japan. NW denotes northwestern parts of Siberia eastwards to but not beyond Taimyr – Putorana. NW–C denotes ranges from northwestern to southern Siberia and central Asia. W denotes temperate western Siberia, a very common extension of ranges where the taxa reach far north in Europe but become much more southern in Siberia. W–C denotes southwestern ranges from the Black Sea and Caucasus regions to central Asia.

Asian Beringian: Confined to the Beringian parts of northeastern Asia, mainly in Chukotka, the Magadan area, and the Koryak area.

Asian Pacific: In coastal / oceanic parts of eastern Asia south of the Beringian areas, often reaching south to Japan.

Circumboreal: More or less continuous throughout the boreal and often the temperate parts of Eurasia and North America (sometimes including southern Greenland).

Circumboreal–polar: A combined circumboreal and circumpolar pattern, from boreal/temperate to arctic.

Circumpolar: More or less continuous throughout the arctic and often the northernmost boreal parts of Eurasia and North America (including Greenland) but excluding the temperate mountain ranges.

Circumpolar–alpine: Circumpolar and with occurrences in one or more temperate mountain ranges south of the boreal zone.

Cordilleran: In the western North American mountains, sometimes north to the Yukon Territory and Alaska. S denotes ranges mainly south of the Pleistocene glaciations, southwards from southern British Columbia and Alberta.

Cosmopolitan: Globally widespread and present on all continents (except for Antarctica).

European: From the Urals, the Caspian Sea, and the Caucasus westwards. In the north, we consider the Urals, the Yugorskiy Peninsula, Vaigach, and Novaya Zemlya to be parts of Europe. If there is no specification, the taxon is widespread in the European parts. C denotes Europe north of the Mediterranean parts and south of the Nordic area and northern Russia, in most cases the central European mountains. C–NE denotes ranges reaching from central Europe to northeastern European Russia but avoiding northwestern (Nordic) Europe. C–S denotes Europe from Germany and Poland southwards, including the sourroundings of the Mediterranean and sometimes the Caucasus. C–SE denotes central and southeastern Europe (the Balkan). E denotes eastern Europe, mostly European Russia, Belarus, Ukraine, and sometimes from Poland south to the Balkan. N/C denotes ranges disjunct between northern Europe and the central European mountains, mostly for arctic–alpine taxa. N denotes northern temperate, boreal, and/or arctic Europe in Iceland, Fennoscandia, Svalbard, and/or northwestern European Russia (the Murman area and southwards), sometimes also east of the White Sea. NE denotes northern temperate, boreal, and/or arctic northeastern European Russia, mainly east of the White Sea. SE/NE denotes a rare type of ranges disjunct between the Balkan and northeastern European Russia. SE denotes southeastern Europe, mainly the Balkan. W denotes western Europe east to Scandinavia, Germany, and the Alps.

European Atlantic: In coastal / oceanic regions of western Europe including Iceland. N denotes ranges from the British Isles and northwards. NW denotes ranges mainly confined to the British Isles, the Faeroes, Iceland, and westernmost Norway.

North American: If there is no specification, the taxon is widespread more or less across North America from the Pacific to the Atlantic, and from temperate at least north to boreal parts. C–E denotes ranges from the central ('prairie') parts and eastwards. E denotes eastern U.S.A. and Canada, sometimes also southern Greenland. N denotes the northern (boreal and/or arctic) parts. NE denotes northeastern temperate, boreal, and/or arctic parts of North America, mainly in Canada and Greenland but in some cases extending to the northern New England states. NW denotes northwestern parts, reaching well outside the Beringian areas into at least western / northwestern Canada. NW–C denotes ranges extending from the northwest into the central ('prairie') regions. SW denotes southwestern U.S.A. W denotes western (Cordilleran and Pacific) parts. W–C denotes ranges extending from the western parts into the central ('prairie') regions. Greenlandic denotes that the taxon is restricted to Greenland.

South American: Referring to bipolar distributions with an often strongly isolated part area in southernmost South America, denoted as S, or to larger parts of South America.

Southern Hemisphere: Present in two or more major regions in the Southern Hemisphere.

Tropical mountains: Present in two or more major ranges of tropical mountains.

Ranges are described from west to east (and south). Where parts of ranges are more or less connected, this is denoted with '–'. Where there are large disjunctions, this is denoted by '&'. Example (Aruncus dioicus):

G European (C–S) & Asian (C) & Asian (NE) – amphi-Pacific & North American (E).

Which means four disjunct parts of the range in central and southern Europe, in southern Siberia and central Asia, in an area from northeastern Asia across the North Pacific to western North America, and in eastern North America.

6.4  Notes

In the opinion of the Editors, the Notes are the most important part of the Checklist besides the choice of accepted name and taxonomic status. The notes constitute more than 50 % of the Checklist text and are mostly summaries of comments made by the Editor-in-Chief, by the PAF collaborators and by external reviewers. Assigned comments in the notes are due to specific persons. Unassigned comments are due to the Editor-in-Chief (Elven).

The notes indicate taxonomic and nomenclatural problems, arguments for the choices made, prospects of future work, and also cases where we have not reached agreement on treatments and why. Alternative treatments to those chosen for the Checklist are discussed. Comments to previously circulated drafts that have been made obsolete by decisions in their favour have, however, mostly been omitted.