Panarctic Flora

470201 Rhodiola rosea L.

• L., Sp. Pl.: 1035 (1753). Lectotype (LINN): Europe. Herb. Linn. 1186.1 (Ohba in Jarvis et al. 1993: 81). - Sedum rosea (L.) Scop., Fl. Carniol., ed. 2, 1: 326 (1771).

2n= 22 (2x, x = 11). - See subspecies below.

Geography: Amphi-Atlantic - European - Asian.

Notes: Elven, Korobkov, and Murray: The range of Rhodiola rosea depends on how it is circumscribed vs. the amphi-Beringian and Cordilleran R. integrifolia and the Siberian R. borealis. Hultén (1968a) excluded Siberian and northwestern North American plants from R. rosea s. str., i.e., he excluded both R. integrifolia and R. borealis (which he merged as Sedum rosea subsp. integrifolium, see below). Petrovsky (1984) accepted R. rosea east to the Bering Strait, which means that he included R. borealis in it. Hultén and Fries (1986) mapped what they called "yellow-flowered taxa" from Siberia, the Russian Far East, and the Alaskan Seward Peninsula. Moran (2009) accepted R. rosea from Alaska, probably on the authority of Hultén.

Peschkova (1994c) mapped R. rosea s. str. with a southern and distinctly non-arctic range in Siberia. She assigned the northern Siberian plants to R. borealis characterized vs. R. rosea by, e.g., leaves glaucescent, later erubescent, ovate or orbicular vs. green, oblong or narrowly oval, and follicles 3.5-5 (6) mm, oval-oblong or ovate, violet-reddish and one-sided vs. 6-8 mm, oblong-lanceolate, brown or green, sometimes reddish, and more symmetrical. Bezdeleva (1995) mapped only R. rosea from the Arctic in the Russian Far East, whereas she included R. borealis in R. integrifolia. Some critical study of the material is needed before it is finally decided whether R. borealis should be accepted as a separate species or race and whether it also occurs in the Russian Far East and western Alaska. We enter two races of R. rosea as subsp. rosea and subsp. borealis but exclude the very few yellow-flowered western Alaskan plants from this species. These plants are identical to R. integrifolia in all other features, especially in the differentiating leaf shape (oblanceolate-obovate with acute to acuminate apex), and they mainly occur as scattered plants within otherwise red-flowered populations (ALA).

We consider R. integrifolia specifically different from R. rosea s. lat. The majority of the chromosome counts of 2n = 22, characteristic of R. rosea but different from R. integrifolia (2n = 36), come from the North Atlantic regions and the western parts of Russia, but there are also Siberian and Asian Beringian counts of 2n = 22 from within the range of subsp. borealis.