Panarctic Flora

641041 Potentilla macrantha Ledeb.

• Ledeb., Mém. Acad. Imp. Sci. St. Pétersbourg Hist. Acad. 5: 541 (1815). Described from "Jacutia" (Siberia), leg. Ledebour. Syntype in Praha (PR-378005).
• Potentilla jacutica Juz., Fl. URSS 10: 611, 141 (1941). Described from "e vicin. oppid. Jakutsk" in Yakutia (Siberia). Type in LE.
• Potentilla evestita auct., non Th. Wolf (1980).

2n= 28 (4x). - Siberia (N), Asia (C), Far East (N). - Several reports, numerous counts.

Geography: European (NE) & Asian (NE): RUS RFE.

Notes: Yurtsev (PAF proposal) assumed Potentilla macrantha to be a hybrid species from crosses between unidentified species of sect. Aureae and sect. Niveae. Soják (2004) proposed the parentage to be from P. crebridens or P. nivea x P. stipularis. As to the name and synonymy, Yurtsev commented that the identity of P. jacutica with the type specimen of P. macrantha Ledeb. is accepted after Soják (in comment), confirmed by Soják (2005).

Eriksen: Here is something dubious! That P. macrantha = P. jacutica is possible but then not identical with Soják's neotype of P. jacutica. The type of P. macrantha (LE) looks like a member of section Niveae but with a slight tomentum. Outside the Arctic? Why did Soják select a neotype for P. jacutica? The neotype does not fit the original description very well although Juzepczuk annotated the sheet.

Yurtsev: Potentilla macrantha is a boreal northern Asian meadow-steppe species with its main range in eastern Siberia and a rather disjunctive distribution: common in West Chukotka, with sporadic occurrence in the easternmost Chukchi Peninsula (one locality) and the Bolshezemelskaya Tundra (three localities). It is a plant with a rather original combination of characters, e.g., petioles of rosette leaves with a combination of sparse long and short stiff patent verrucose hairs along with numerous subsessile glands, leaflets broad, the terminal one more often sessile, with numerous teeth, with lax floccose pubescence and numerous glands beneath, and pilose veins, the stem leaves often 4-5-nate, the lower lobes adnate with stem as in [P. stipularis]. Pedicels are glandulose and shortly puberulose (a distinction from the related central Asian P. evestita with tomentose pedicels) but the outer leaves of the rosette lack tomentum. One can suggest a more continuous distribution in one of drier phases of the Pleistocene.

Elven: Yurtsev reported P. macrantha to be very disjunct: rare in the northern Urals, non-arctic in northeastern Yakutia, frequent in West Chukotka, and rare in East Chukotka. Its range then is within the general range of the rarer of its proposed parents (P. stipularis). This might be an acceptable species with a consistent range in Yakutia (non-arctic) and West Chukotka but perhaps not in northeastern Europe and East Chukotka. Yurtsev's suggestion of reduction of a previously larger and more continuous range is pure guesswork. Note, however, the repeated counts of a tetraploid chromosome number (2n = 28). Is this really an agamospermous hybrid species?