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FNA | Family List | FNA Vol. 9 | Rosaceae | Potentilla

8b. Potentilla Linnaeus sect. Biflorae (Rydberg) O. Stevens in N. L. Britton et al., N. Amer. Fl. 22(7): 11. 1959.

Reidar Elven, David F. Murray, Barbara Ertter

Potentilla [unranked] Biflorae Rydberg, Bull. Torrey Bot. Club 24: 13. 1897; Potentilla ser. Biflorae (Rydberg) Soják; Potentilla subg. Micropogon Bunge

Perennials, tufted, not stoloniferous; taproots not fleshy-thickened; vestiture of long and crisped hairs, glands absent or sparse, not red. Stems ± erect, not flagelliform, not rooting at nodes, lateral to persistent basal rosettes, (0.1–)0.5–1(–1.5) dm, lengths 1.5–3 times basal leaves. Leaves: basal sometimes 2-ranked; cauline leaves 0(–1); primary leaves ternate, appearing ± palmate, 2–7 cm; petiole: long hairs absent or spreading to ascending, weak, glands usually absent; leaflets 3, at tip of leaf axis, separate, cuneate-ovate in outline, margins strongly revolute, central leaflets divided nearly to base into 3 equal lobes, lateral divided nearly to base into 2 lobes, lobes entire, rarely again 2-fid, surfaces ± dissimilar, abaxial whitish with thick waxy bloom, cottony hairs absent, adaxial light green, often purple-tinged, not glaucous, long hairs weak or absent. Inflorescences solitary flowers or 2–3(–4)-flowered, ± cymose, open. Pedicels straight in fruit, 0.5–1.5(–2) cm, proximal not much longer than distal. Flowers 5-merous; hypanthium 2–2.5 mm diam.; petals pale yellow to yellow, ± obcordate, 6–10 mm, longer than sepals, apex retuse; stamens ca. 20; styles subapical, filiform-tapered, not papillate-swollen proximally, 2.5–4 mm. Achenes smooth.

Species 1: nw North America, Asia.

Although sect. Biflorae deviates from the main body of Potentilla and superficially resembles the mainly Asian genus Dasiphora in shoot and leaf architecture and in some floral features, molecular analyses place the species unequivocally in the Potentilla clade, not in the Fragaria clade with Dasiphora (C. Dobeš and J. Paule 2010; M. H. Töpel et al. 2011).


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