Panarctic Flora

641020 Potentilla petrovskyi Soják

• Soják, Cas. Nár. Mus., Odd. Prir. 153: 102 (1984). Holotype (LE): Russian Far East: South Chukotka, "Anadyr, r-n. ch. Pekulnej, r. Sev. Pekulnejveem", 1977, leg. Vassiljeva 77-212.
• ?Potentilla tschaunensis Juz. ex Jurtz., Fl. Arct. URSS 9, 1: 317, 165 (1984). Holotype (LE): Russian Far East: West Chukotka, "districtus Czaunensis, regio ripae sinistrae fl. Olvegyrgy-vaam", 23. June 1951, leg. I.P. Schmorgunova.

2n= (1) 28 (4x). - Far East (West Chukotka). - Zhukova and Petrovsky (1985b, two counts within populations with 2n = 56, one additional count for P. tschaunensis).
(2) 56 (8x). - Far East (West Chukotka). - Zhukova and Petrovsky (1985b, seven counts, one additional for P. tschaunensis).

Geography: Amphi-Beringian (W): RFE ALA.

Notes: Yurtsev 2000: The parent from section Niveae is not identified. Potentilla petrovskyi and P. tschaunensis both have wool on the petioles (under straight inclined longer hairs typical of P. anachoretica). In P. petrovskyi the wool is short and crispate, whereas in P. tschaunensis it is long and floccose (as in P. nivea or P. crebridens). Leaves in P. petrovskyi are mostly shortly pinnate, in P. tschaunensis mostly semidigitate. Flowers in the former are smaller with shorter styles not or weakly incrassate at the base, in the latter styles longer, incrassate. So, I do not see any danger to the above species to be omitted or merged with P. borealis. All of them have combinations of stable distinctions and extensive ranges of their own.

Elven: Soják (2004) assumed Potentilla petrovskyi to be a hybrid species from P. anachoretica and P. nivea s. lat. and synonymized the names P. tschaunensis and P. petrovskyi due to the same assumed parentage. Soják's synonymization was based on the principle that all offspring from a specified parental combination should be included under one name. It does not take into account the morphological differences emphasized by Yurtsev above.

Elven and Murray: Potentilla petrovskyi and P. tschaunensis may be agamic hybridogeneous biotypes arisen here and there within the contact zones of the parents. We can confirm Beringian Alaskan occurrence of plants that conform to Yurtsev's description but from an area where P. anachoretica is not yet known (the Seward Peninsula). No other (related) pinnate-leaved species is known from this region.