Panarctic Flora

6711 Parrya R. Br.

• R. Br., Chlor. Melvill.: 10 (1823).
• Neuroloma Andrz. in DC., Prodr. 1: 156 (1824).
• Achoriphragma Soják, Sborn. Nár. Muz. v Praze 1982, 1-2: 105 (1982).

Notes: Elven and Murray: The two other generic names above are based on a possible split of Parrya. Botschantzev (1972) considered Parrya monotypic (P. arctica alone). The other species he divided on Neuroloma and Leiospora (C.A. Mey.) Dvorák, Spisy Prír. Fak. Univ. v Brne 497: 356 (1968). Soják (1982) stated that Neuroloma Andrz. ex DC. 1824 is a later homonym for Nevroloma Raf. 1819 and coined the new generic name Achoriphragma. We consider P. nudicaulis to be very closely related to P. arctica and find the proposed division of them on two genera unacceptable.

The arctic plants of Parrya are currently accepted as belonging to three species. Parrya arctica is the type species of the genus and confined to the Canadian Arctic Archipelago and the mainland coast. Parrya nudicaulis is temperate to arctic, northern Eurasian and widely amphi-Beringian, and polymorphic. The recently described P. nauruaq is a local species on the Seward Peninsula in western Alaska. No experimental investigation of Parrya is known to us but a possibly intricate structure is found among the arctic representatives.

Within P. nudicaulis, Hultén and Fries (1986: map 918) accepted three northern races with overlapping (parapatric) ranges. They mapped subsp. nudicaulis to be the geographically major race from northwestern European Russia (e.g., Novaya Zemlya) throughout northern Siberia and the Russian Far East (south to the Kuriles and Okhotsk Sea), and to western and northern Alaska and northwestern Canada. This is a range extension in North America compared with Hultén (1968a), where he in North America mainly accepted it from coastal western Alaska. Hultén (1945a) described the plants of interior Alaska and the Yukon Territory as subsp. interior, deviating in narrower and entire or subentire leaves and less glandular pubescence (however, many eastern plants are just as glandular as the western ones that Hultén assigned to subsp. nudicaulis). Hultén (1968b) described subsp. septentrionalis to encompass deviating narrow-leaved and eglandular, arctic plants from northern Alaska east to the Mackenzie River (and Victoria Island), and also the northernmost plants of Russia west to Gydan (between the Ob and Jenisei rivers). Hultén (1968b: 67) stated, in connection with subsp. septentrionalis: "P. arctica R. Br. is also completely glabrous and doubtless closely related. It is a high-arctic much reduced plant, with almost linear leaves". Subsequently, Hultén (1971a: 42, map 34; repeated by Hultén and Fries 1986: map 918) included P. arctica in P. nudicaulis subsp. septentrionalis with the argument: "In America it has been customary to regard the high-arctic plant as a species, P. arctica R. Br. In my opinion it is better regarded as a glabrous race of P. nudicaulis: subsp. septentrionalis Hult. ... P[arrya arctica] R. Br. is probably a high-arctic extreme with nearly linear leaves of subsp. septentrionalis". What Hultén does not comment on is the floral differences, e.g., much smaller flowers, shorter anthers (mostly ca. 1 mm vs. 1.2-2 mm in P. nudicaulis), and some difference in fruits (those in P. arctica not torulose as they are in P. nudicaulis). Researchers who have seen both P. arctica and P. nudicaulis (including subsp. septentrionalis) usually have no problem accepting two species in the field. In addition to the northern races, Hultén and Fries (1986) accepted an isolated subsp. rydbergii (Botsch.) Hultén in the southern Rockies, and subsp. turkestanica (Korsh.) Hultén and some unnamed races in the southern Siberian and central Asian mountains. On the Russian side, Petrovsky (1975b) accepted only a collective P. nudicaulis for the northern parts but he accepted P. arctica as a species apart.

Löve and Löve (1975a) followed Hultén in principle, synonymizing P. arctica and P. nudicaulis subsp. septentrionalis, but they considered it a species and assumed it to be diploid (2n = 14) in contrast to P. nudicaulis s. str. which they considered to be tetraploid (2n = 28). They sorted chromosome counts accordingly. This sorting was erroneous.

Rollins (1993) did not accept Hultén's subspecies of P. nudicaulis but he accepted P. arctica. He did not discuss or evaluate the possible connection between P. arctica and Hultén's subsp. septentrionalis.

The polymorphy is pronounced and partly investigated on the American side (e.g., by Hultén and by J. Grant in an unpublished treatment) but not on the Russian side. It is difficult, without some experimental data, to know what to do. Any conclusion will have to be based on morphology alone. Our experience with Hultén's treatments in general is that we often can agree with - or at least understand - his taxonomic conclusions, but that his 'morphology' often was scanty and imprecise. He had a sharp eye for the plants but he did not always specify the diagnostic characters very well (not surprising when one realize how many species he formed his opinions on in the circumpolar room). This is also the case with northwestern North American Parrya (except for P. arctica, which he probably never did see in the field). We can see differences between coastal western Alaskan plants and the interior Yukon Territory plants, and also between both these groups and the northern plants, but when we try to apply Hultén's characters we find them mixed within populations, e.g., in western Alaska.

Parrya nudicaulis s. str. is most probably continental northeastern Asian in origin with migration to North America through Beringia. Subspecies interior may be a Pleistocene isolate in interior East Beringia (as subsp. rydbergii may be an isolate south of the Cordilleran glaciers and P. nauruaq at the Bering Strait). Parrya arctica and subsp. septentrionalis may be more (arctica) or less (septentrionalis) differentiated parts of a northern, late Pleistocene Shelf taxon, separated postglacially by the sea gap between the Canadian Arctic Archipelago on one side and the northern Yukon Territory and northern Alaska on the other. Secondary contact between P. nudicaulis s. str. and subsp. septentrionalis seems to have taken place postglacially both in northern Siberia and in northern and northwestern Alaska. This will, however, be pure guesswork until some experimental and molecular investigation is undertaken.

We accept three species - P. arctica, P. nauruaq, and P. nudicaulis - the last-mentioned with two subspecies.