Panarctic Flora

641005 Potentilla anachoretica Soják

• Soják, Preslia 46: 70 (1974). Holotype (LE): Russian Far East: West Chukotka, "districtus Tschaunskij, ad ripam sinistram cursus inferioris rivi Olvegyr-gyvaam", 22. June 1951, leg. I.P. Schmorgunova.
• Potentilla czukczorum Jurtz. & V.V. Petrovsky in Jurtz., Probl. Bot. Geogr. Sev. Azii: 61 (1974) nom. nud..
• Potentilla arctica auct., non Rouy (1900).

2n= (1) 14 (2x). - Siberia (N). - Zhukova and Petrovsky (1985b). See notes.
(2) 28 (4x). - Siberia (N), Far East (N). - Three reports, more than 20 counts.
(3) 42 (6x). - Far East (N). - Zhukova and Petrovsky (1977, 1985b).
(4) 56 (8x). - Far East (N). - Zhukova and Petrovsky (1985b, one count in a population with 2n = 28).
The numbers 2n = 28, 42, and 56 are counted on material identified as var. anachoretica.

Geography: Amphi-Beringian (W).

Notes: Yurtsev: Potentilla anachoretica represents a xerophilous morphotype of a petrophyte with strongly branched caudex, leaflets deeply dissected into numerous linear segments, larger flowers than in the P. multifida aggregate with obcordate petals, and lateral leaflets (4-8) remote, upper ones with much more numerous teeth, acute. The wool of the lower side of leaves is crispate, totally covered with brightly white straight verrucose hairs. It is an ancient Megaberingian element of the Arctic flora, mostly Asian, spread from the central Byrranga Mountains (Taimyr) to the northern slope of the Brooks Range (northern Alaska) with greatest occurrence in Chukotka. It is common in the drier parts of Wrangel Island. In some areas with dry climate (southwest-central Wrangel Island; right bank area of Palavaam River, the Amguema River higher terraces) the species is common in cryophyte steppes on south-facing slopes. It is interesting that, besides three polyploid chromosome numbers (2n = 28, 42, 56), the species has a diploid karyorace (2n = 14) on limestones of the Chersky Range in subarctic northeastern Yakutia, somewhat distinctive in, e.g., ultrastructure of hairs. One more race, described as var. planiuscula, resembles in shape of leaf some other species of Potentilla, e.g, P. lyngei and P. wrangelii. One can meet it in a few localities in Chukotka, sometimes sympatric with the type race. All three types differ in some details of ultrastructure of leaf pubescence (Eriksen and Yurtsev 1999). Whereas P. anachoretica s. str. has crispate wool and verrucose straight hairs, the diploid race has smooth straight hair on the upper side of leaves (otherwise verruose), and var. planiuscula has a mixture of crispate and floccose flat, crinkly hairs on lower side of leaf blades. The status of the diploid race and of var. planiuscula needs specification (at present only one population of the four from northeastern Yakutia has been studied cytotaxonomically).

Elven and Murray: The variation obviously merits further study. Until that is accomplished, the two named varieties are entered provisionally. The diploid karyorace does not seem to reach the Arctic.

The mainly Asian P. anachoretica (description and illustration by Soják 1974b) is now unambiguously confirmed from one or perhaps two localities in northern Alaska, based on collections deposited in S and studied by Soják and by us. The rare occurrence of P. anachoretica on the American side is accompanied by reports of a hybrid species there with P. anachoretica in its assumed parentage (P. murrayi).