Panarctic Flora

641036 Potentilla nivea L.

• L., Sp. Pl.: 499 (1753) nom. cons.. Neotype (GB): Sweden: Torne lappmark, the Abisko area, Latnjajaure, leg. B. Eriksen 620 typ. cons. (Eriksen et al. 1999a: 165).
• Potentilla prostrata subsp. floccosa Soják, Candollea 44: 751 (1989). Holotype (PR): France: Hautes-Alpes, Le Lautaret, à-Prime-Messe, 1909, leg. Faurie.

2n= (1) 49 (7x). - Far East (Wrangel Island). - Petrovsky and Zhukova (1981, for P. nivea subsp. fallax).
(2) 56 (8x). - Europe (N), Far East (N), Canada. - Several reports, numerous counts, partly for P. nivea subsp. mischkinii and subsp. fallax.
(3) 63 (9x). - Europe (N), Greenland. - Four reports.
Not included: Reports of 2n = 14 (2x) from southern Siberia (Krogulevich 1976b, 1978) and of 2n = 28 (4x) from southern and northern Siberia and the northern Far East (several reports) probably belong to P. crebridens. A report of 2n = 49 (7x) from southern Siberia (Belaeva and Siplivinsky 1976) probably belongs to a relative as do at least five reports of 2n = 70 (10x) from Japan and Chukotka.

Geography: Circumpolar-alpine: NOR RUS SIB RFE ALA CAN GRL.

Notes: Elven and Murray: The meaning of the name Potentilla nivea depends on the type. The name was until the 1940's applied collectively for current-day P. arenosa s. lat., P. crebridens s. lat., P. nivea, and some others. With the description of three new species with non-floccose petiole hairs - P. arenosa (Turcz.) Juz. and P. kuznetzovii (Govor.) Juz. (Juzepczuk 1941), and P. chamissonis Hultén (Hultén 1945b) - and a study of the eastern Fennoscandian variation (Hiitonen 1947), the name was more firmly attached to the group of P. nivea and P. crebridens with petiole hairs floccose. Hultén (1945b) annotated one of the two original LINN elements (Scandinavian) as his new P. chamissonis (= P. arenosa subsp. chamissonis). He assumed the other element to belong to P. nivea in the customary European meaning, i.e., with petiole hairs floccose. It does not. Both the specimens available as types (LINN) lack floccose hairs but have the long, stiff, verrucose hairs of P. arenosa s. lat. The other specimen is most probably from Siberia (leg. Gmelin) and belongs to P. arenosa subsp. arenosa as shown by Soják (1989). Linnaeus' protologue reported the plant from northern Scandinavia ("Lapponiæ") and Siberia and his description could fit both P. nivea s. lat. and P. arenosa s. lat. Soják (1989) was aware of this complication and correctly accepted P. nivea L. to be the priority name for the plant without floccose hairs, replacing the name P. arenosa (Turcz.) Juz. He proposed a new name - P. prostrata Rottb. subsp. floccosa Soják - for the central and northwestern European and Greenland plant with floccose hairs, customarily considered as P. nivea s. str. Soják's procedure did not win much acclaim and later he (Soják 2004) identified P. prostrata Rottb. 1770 s. str. with the hybrid P. chamissonis x nivea. Eriksen et al. (1999a) rather proposed to retain the name P. nivea for what since 1945 has gone by that name by selecting a plant with petioles with floccose hairs as a neotype proposed for conservation. This proposal is now ratified by the Code (McNeill et al. 2006: 459) and has to be followed.

Yurtsev (PAF proposal and elsewhere) accepted two races of P. nivea: a non-arctic European subsp. nivea (probably influenced by Soják's typification of P. prostrata subsp. floccosa on material from the French Alps) and a nearly circumpolar subsp. mischkinii. Subspecies mischkinii combines floccose and verrucose hairs on the petioles. We consider such plants as hybrids or hybrid species between P. arenosa s. lat. and P. nivea s. lat. Such plants are provisionally entered below as two species: P. prostrata (P. mischkinii) and P. drymeja (P. tomentulosa). Soják (in comment) stated that also P. chamissonis belongs in this hybrid group but we do not accept that assignment (see notes to P. arenosa below). Yurtsev's comments concerning this question are included under P. prostrata. Yurtsev's comments were made before Eriksen et al. epitypified P. nivea. As P. nivea now is based on a type from northern Sweden, and as this plant is the same as the arctic Scandinavian and Svalbard plant in morphology and molecular markers (Nyléhn 1999; Hamre 2000; Hansen et al. 2000; Nyléhn et al. unpubl.), the name P. nivea (s. str.) is relevant for an arctic plant.

Whether there are recognizable races in P. nivea remains to be decided. There is some molecular support (Eriksen and Töpel 2006) for acceptance of two groups: one broadly Beringian and one broadly Atlantic. The North Atlantic group of P. nivea would include the type of the species and would be subsp. nivea. The possible Beringian group is without name. The possibility of two major races is supported by the North American morphological variation (see Elven 2007). There is a change in morphological features in P. nivea from Greenland and northeastern Canada to northwestern Canada and Alaska. The eastern plants have, e.g., densely and nearly purely floccose petioles and shallowly dissected leaflets with comparatively few, rounded teeth. The western plants are less densely and more mixed hairy and have more deeply dissected leaves with more numerous and partly subacute teeth.

Within the Atlantic group, the populations in the non-arctic coastal mountains of northwestern Scandinavia differ (slightly) from the main Scandinavian and Svalbard plants in molecular markers and are also recognizable morphologically without any possible local 'hybrid' explanation (Nyléhn et al. unpubl.). Morphologically, this northwestern Norwegian plant resembles the arctic plants in Greenland and northeastern Canada more than the ones elsewhere in Scandinavia. This population group exemplifies that some of the segregates of P. nivea may merit rank when sufficiently investigated and documented.