Panarctic Flora

671603 Cardamine polemonioides Rouy

• Rouy in Rouy & Foucaud, Fl. France 1: 234 (1893). Described from Svalbard "Spitzbergen" (Norway), Novaya Zemlya (European Russia), and from Iceland. - Cardamine pratensis subsp. polemonioides (Rouy) auct. (see notes).
• Cardamine pratensis var. angustifolia Hook., Fl. Bor.-Amer. 1: 45 (1829). Described from Southampton Island in Nunavut (Canada). - Cardamine pratensis subsp. angustifolia (Hook.) O.E. Schulz, Bot. Jahrb. Syst. 32: 529 (1903).
• Cardamine nymanii Gand., Bull. Soc. Bot. France 72: 1043 (1926). Type: Norway: Svalbard Spitzbergen, "Kingsbay 79N", leg. Schäfer. Isotypes in O!

2n= 56-ca. 100. - Europe (N), Russia (N), Far East (N), Alaska. Canada, Greenland. - Numerous reports. See notes.

Geography: Circumpolar: ICE NOR RUS SIB RFE ALA CAN GRL.

Notes: The question has been asked (e.g., by Petrovsky) whether there is one or more high-arctic taxa of the Cardamine pratensis group. Three names are relevant, all indubitably referring to arctic plants: Hooker's var. angustifolia based on plants from Southampton Island in Nunavut, Canada; Gandoger's C. nymanii on plants from Svalbard; and Rouy's C. polemonioides on plants from 'Spitzbergen' = Svalbard, Novaya Zemlya, and Iceland. In the two first regions only a high-arctic taxon of the C. pratensis group is known, in the last-mentioned area an arctic taxon is the one certainly native and perhaps the only one.

The reported chromosome numbers concentrate at two levels. Numbers of 2n = 56, 64 (and 68) are reported from Hudson Bay, Greenland, Svalbard, Iceland, Fennoscandia, and northern Russia, i.e., the broadly amphi-Atlantic regions. Numbers of 2n = 80-100 are reported from Chukotka, Alaska, and Hudson Bay, i.e., the broadly amphi-Beringian and North American regions. Both levels are reported from the Hudson Bay area from where subsp. angustifolia was described, whereas the lower level only is reported from the type areas of C. nymanii and C. polemonioides. The ploidy levels might suggest some difference between the plants in the broadly considered amphi-Atlantic and amphi-Beringian regions, perhaps with those in the amphi-Beringian regions as most derived from the assumed European low-ploid origin.

Petrovsky commented that C. polemonioides can be merged with subsp. angustifolia only if the former taxon was described from arctic America; otherwise, both taxa should be considered separately along with C. dentata. As stated above, the name C. polemonioides is of European origin. We have compared plants from arctic Europe (Norway, Svalbard, Iceland), Siberia (Yakutia, Chukotka), Greenland, and arctic North America, in the field and in herbaria. Some of the North American plants named as subsp. angustifolia have narrower leaflets than the majority of the Eurasian ones but similar plants occur also on the European side, e.g. in the mountains of northern Scandinavia (Lövkvist 1956, 1957; Nilsson 1986: 106), and plants with broader leaflets, indistinguishable from the ones in Svalbard, Scandinavia, and Siberia, are frequent in arctic Canada and Alaska. We therefore provisionally assume that there is only one major arctic taxon. If two taxa are accepted, the plants of Chukotka and North America east to Hudson Bay belong to subsp. angustifolia (and perhaps some farther east, e.g., in northern Scandinavia), whereas at least the large majority of those from Hudson Bay eastwards across Greenland and northern Europe to northern Siberia belong to C. polemonioides.

European authors have often applied the combination C. pratensis subsp. polemonioides Rouy (e.g., Jones and Marhold 1993). As far as we can see from the original text, Rouy in Rouy and Foucaud (1893) described C. polemonioides as a species. How it became a subspecies in later works (including Flora Europaea), we do not know. The name C. polemonioides has priority if the taxon is accepted as a species. Al-Shehbaz et al. (2010b) applied the name C. nymanii.