Panarctic Flora

500703 Saxifraga hirculus L.

• L., Sp. Pl.: 402 (1753). Lectotype (LINN): Probably Sweden. Herb. Linn. 575.38 (Siplivinsky 1977: 99). - Leptasea hirculus (L.) Small, N. Amer. Fl. 22, 2: 152 (1905). - Hirculus ranunculoides Haw., Saxifr. Enum.: 40 (1821). Nomen novum for Saxifraga hirculus L.

2n= (1) 16 (2x). - Europe (C), Asia (C), Far East (N), Alaska, Canada, U.S.A. (W). - Numerous reports, partly for "propinqua" or "prorepens".
(2) 24 (3x). - Canada (N). - Hedberg (1967, 1992).
(3) 28. - Asia (C). - Sokolovskaya and Strelkova (1938, 1948a).
(4) 32 (4x). - Europe (N, C), Russia (N), Siberia, Far East (N), Canada, Greenland. - Numerous reports.

Geography: Circumboreal-polar.

Notes: Saxifraga hirculus s. lat. is a polymorphic species or species group for which there are two proposals.

Zhmylev: Saxifraga hirculus is a circumboreal-polar species of considerable morphological variability. Shortly rhizomatous, diploid and tetraploid plants (2n = 16, 32), often treated as subsp. propinqua, are found in the high-arctic regions and in mountain ridge tundra. In southern tundra, in wet mires and damp meadows are found tetraploid plants with long rhizomes, subsp. hirculus. However, the other characters (e.g., shape of petals and sepals, flowers number) are only slightly correlated with growth form. Ecological and/or morphological races of S. hirculus should probably not be accepted at subspecific or specific rank.

Elven and Murray: Zhmylev did not comment upon the monographic treatment of Hedberg (1992). Hedberg argued for S. hirculus s. lat. as a boreal-arctic aggregate developed from the very diverse Himalayan centre of sect. Ciliatae. He stated that 54 species were known (or at least named) from Nepal alone. He accepted one northern species with four subspecies, three as present in the Arctic: a tetraploid subsp. hirculus in Europe, Siberia, Alaska, and Canada; a diploid subsp. propinqua in East Chukotka, Alaska, Canada, and northwestern Greenland; and a tetraploid subsp. compacta in eastern Greenland, Iceland, Svalbard, northeastern European Russia, Siberia, the Russian Far East, Alaska, and northwesternmost Canada. A diploid subsp. coloradensis Hedberg was recognized from western U.S.A.: Colorado. Hedberg presented cytological and morphological arguments for his proposal, including a key.

Oliver et al. (2006) studied chloroplast DNA variation in the European and western and northwestern North American parts of its range and found much variation, especially in Alaska, but little support for a consistent taxonomic structure. However, chloroplast markers may be too conservative in an assumedly recently evolved arctic-alpine complex like this. Brouillet and Elvander (2009b) cited the Hedberg treatment but did not accept the subspecies.

We have entered Hedberg's races as we find the morphological variation pronounced, but we, like Zhmylev, Brouillet, and Elvander, are not convinced that the differential characters reported by Hedberg can be applied consistently. Note that Hedberg (1992) only mapped and reported material he had inspected. This resulted in a very thin pattern in the Asian parts of his maps, also for our northern Siberian regions.