Panarctic Flora

0103 Huperzia Bernh.

• Bernh., J. Bot. (Schrader) 1800, 2: 126 (1801).

Notes: The plants of Huperzia that reach the boreal and arctic regions are polymorphic and have been treated taxonomically in several ways in more recent decades. Published treatments by western European, Russian, and North American authors are incompatible. The options are: one undifferentiated species (H. selago), one species with races (subspecies), or several species.

For North America, Wagner Jr. and Beitel (1993) accepted in Huperzia six assumedly basic species, one allopolyploid species, and six spore-sterile hybrids propagating by bulbils and stated to be "extremely common" in some areas. Bulbil reproduction is common as an alternative propagation also among the sexual species. The basic and allopolyploid species of Wagner Jr. and Beitel are divided on two geographical groups. An eastern ("Atlantic") group consists of H. selago s. str. mapped to reach the Arctic on Hudson Bay only, H. appalachiana mapped to reach the Arctic in southern Greenland, the non-arctic H. lucidula (Michx.) Trev., and the southern allopolyploid H. porophila (F.E. Lloyd & Underw.) Holub (from H. appalachiana x H. lucidula). All three possible hybrids between the basic species are reported. A western ("Pacific") group consists of H. haleakalae mapped to reach the Arctic in Alaska and northwesternmost Canada, H. miyoshiana mapped to reach the Arctic in southwestern Alaska, and the non-arctic H. occidentalis (Clute) Kartesz & Gandhi. Also in this group, all three possible hybrids are reported.

One problem for us is that Wagner Jr. and Beitel disregarded the majority of the arctic American plants. Huperzia occurs throughout the Canadian Arctic Archipelago (scattered) and northern Greenland (frequent), see, e.g., Böcher et al. (1978), Porsild and Cody (1980), and Aiken et al. (2007), whereas the maps of Wagner Jr. and Beitel are "empty" for these areas. They may have considered these plants hybrids since reproduction by bulbils predominates among arctic Huperzia. However, if these plants are hybrids, they have a huge range beyond that of any of their presumed parents and should be recognized in some way. Moreover, several authors have reported good spore production in such arctic plants, e.g., Gelting (1934) from eastern Greenland, and we have seen very many specimens with well-developed spores. At least one sexual species is present there. This gap in the treatment of Wagner Jr. and Beitel makes it difficult to apply even to arctic North America. Unassigned plants in northern Greenland border on their H. appalachiana, those in northern non-Beringian Canada on their H. selago s. str., and those in northern Alaska and the Yukon Territory on their H. haleakalae.

Wagner Jr. and Beitel reported several of their species to occur also outside North America. Huperzia selago s. str. was described from Europe and was stated by Wagner Jr. and Beitel to occur in "Europe, Asia". Huperzia appalachiana is morphologically indistinguishable from northern European plants and was stated "possibly to be present in Europe". Huperzia miyoshiana was described from Japan and was stated to occur in "Asia in Japan, Korea, Siberia" i.e., probably the Russian Far East. Huperzia haleakalae was stated to occur in "Asia in Siberia probably the Russian Far East and Pacific Islands in Hawaii". The names applied by the North Americans therefore cannot be neglected by Russians and western Europeans. Also true is that the often older Eurasian names cannot be neglected by North Americans, as was done by Wagner Jr. and Beitel with respect to the North Atlantic and the Russian Asian areas. Several names currently applied in Greenland, northwestern Europe, European Russia, Siberia, and the Russian Far East are absent from their synonymy.

The more recent western European treatments (e.g., Rothmaler 1993; Elven 1994; Hämet-Ahti et al. 1998; Kukkonen 2000; Mossberg and Stenberg 2003) have accepted one species, H. selago, with two or three subspecies: a temperate to boreal subsp. selago, a northern alpine-boreal to southern arctic subsp. appressa (not accepted by all), and a northern arctic subsp. arctica. This solution is based on a hypothesis of gradual divergence of races or species. Several western European authors have regarded subsp. appressa to be transitorial between subsp. selago and subsp. arctica and have not accorded it rank, e.g., Rothmaler (1993) and Kukkonen (2000) who included subsp. appressa in subsp. arctica which they then recorded south to southern Scandinavia and Scotland. Russian authors (e.g., Tzvelev 1999a; Sekretareva 2004) have followed the same line of thought but rather applied specific rank as H. selago, H. appressa, and H. arctica.

For the Checklist, we accept, in principle, the evolutionary hypothesis of Wagner Jr. and Beitel (1993) and consider the taxa as independent species, not intergrading subspecies. We do not, however, always accept their choices of names and their circumscriptions of the species. Major discrepancies are found concerning the names H. appressa and H. appalachiana, the extension of H. haleakalae to Asia, and the absence of the name H. arctica from the North American treatment (see the single species below).

An additional problem is found in chromosome numbers and ploidy levels. Wagner Jr. and Beitel (1993) reported the base numbers x = 67 and 68. They reported counts for only two of their species (but see H. miyoshiana below): H. lucidula as diploid with 2n = 134 and H. selago s. str. as tetraploid with 2n = 268. The last-mentioned number is perhaps in conflict with their contention of H. selago s. str. as a basic (i.e., diploid) species. They did not take into account chromosome number reports from outside North America. Such reports show a much more complicated pattern. We have found reports of the following numbers: 2n = ca. 68 from northern Europe (Hagerup and Petersson 1960, Denmark?, H. selago; Löve and Löve 1961c, Iceland, probably H. appressa); 2n = 88 and ca. 90 (Harmsen in Löve and Löve 1948, Greenland, probably H. appressa; Sorsa 1963a, Finland, H. appressa); and 2n = 264 and ca. 260-272 (several reports from Europe, Canada, and northeastern U.S.A., assigned to H. appressa and H. selago). The numbers 2n = ca. 68, 88, and ca. 90 make the assumption of base numbers of x = 67 and 68 difficult to accept. The numbers 2n = 88 and ca. 90 are well documented from plants from four separate provinces in northern Finland: Enontekiön Lappi, Inarin Lappi, Koillismaa, and Sompion Lappi (Sorsa 1963a; Kukkonen 2000). X = 44 (or 45) may be a base number, x = ca. 34 possibly another. The low-ploid Finnish plants correspond morphologically to H. appressa, which then cannot be neglected as possibly a basic species. The genetic and taxonomic structure in this genus is intricate with some rare (or perhaps extinct) basic diploids and a complicated superstructure of derived polyploids (allo or auto) and fertile, partially fertile, and sterile but bulbil-reproducing plants. The genus urgently needs a global re-investigation.

• 
  
  Source: Rotatebot at Wikispecies