Potentilla anserina |
Potentilla pseudosericea |
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common silverweed, Pacific cinquefoil, silver weed cinquefoil, silverweed |
Mono cinquefoil, Pennsylvania cinquefoil, silky cinquefoil, strigose cinquefoil |
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Caudex branches | sometimes sheathed with marcescent whole leaves. |
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Stems | decumbent to ascending, (0.2–)0.5–1.5(–2.2) dm. |
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Basal leaves | petiole (0.5–)1–15(–25) cm, long hairs absent or sparse to dense, 1.5–3.5 mm; larger leaflets (0.4–)0.5–5(–7) × (0.2–)0.3–2(–3) cm, surfaces: abaxial with long hairs absent or sparse to abundant, not restricted to veins, 0.5–2(–2.5) mm, cottony-crisped hairs usually dense or usually absent (in subsp. groenlandica), adaxial with long hairs absent or sparse to abundant, cottony-crisped hairs usually absent, sometimes sparse to common (especially subsp. yukonensis). |
usually palmate, rarely also ternate on same plant or subpalmate, (1–)2–6(–8) cm; petiole (0.5–)1–2.5 cm, long hairs abundant to dense, ± appressed, 0.5–1.2 mm, stiff, verrucose, crisped hairs common, cottony hairs absent, glands sparse to abundant but usually obscured; leaflets (3–)5–7, proximalmost separated by 0–2 mm, central ± obovate, (0.5–)1–1.5(–2) × (0.3–)0.5–0.8(–1) cm, petiolules 0–1 mm, distal 3/4 to nearly whole margin incised 3/4+ to midvein, teeth 2–4(–5) per side, (2–)3–6(–10) mm, apical tufts 0.5 mm, abaxial surfaces white, long hairs common to abundant, cottony-crisped hairs dense, short hairs and glands absent or obscured, adaxial grayish green, long hairs abundant, 0.5–1.5 mm, ± stiff, short-crisped (rarely ± cottony) hairs sparse to common, glands absent or sparse. |
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Cauline leaves | 1–3. |
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Inflorescences | (1–)3–10(–20)-flowered, congested or ± elongating in fruit, branch angle 5–30°. |
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Pedicels | 0.2–0.7 cm, proximal to 1.3 cm. |
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Flowers | epicalyx bractlets narrowly to broadly ovate-triangular or linear to elliptic, (2–)2.5–7(–8) × (0.3–)0.5–3(–3.5) mm, often 2-fid or dentate; sepals (3–)3.5–7(–9) mm, apex subacute to acuminate; petals (4–)5–15(–20) × (2.5–)3–10(–12) mm; filaments (1–)2.5–3.5(–4.5) mm, anthers 0.7–1.3 mm; carpels (10–)20–200(–250). |
epicalyx bractlets narrowly elliptic, (1–)1.5–2.5(–3) × 0.5–1 mm; hypanthium 3–4 mm diam.; sepals 2–4(–5) mm, apex obtuse to bluntly acute, glands sparse, obscured; petals pale yellow, not overlapping, 2–4 × 2–3 mm, ± equal to sepals (slightly longer than in Inyo County); filaments 1–1.5 mm, anthers 0.3–0.5 mm; carpels 30–50, styles 1–1.2 mm. |
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Achenes | 2 mm. |
1–1.4 mm. |
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Potentilla anserina |
Potentilla pseudosericea |
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Phenology | Flowering summer. | |||||||||||||
Habitat | Alpine fellfields, moist gravel, talus, on dolomite and quartzite | |||||||||||||
Elevation | 3200–3600 m (10500–11800 ft) | |||||||||||||
Distribution |
AK; AZ; CA; CO; CT; IA; ID; IL; IN; MA; ME; MI; MN; MT; ND; NE; NH; NM; NV; NY; OH; OR; RI; SD; UT; VT; WA; WI; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; Mexico; South America (Argentina, Chile); Eurasia; Pacific Islands (New Guinea, New Zealand); s Australia
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CA
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Discussion | Subspecies 4 or 5 (4 in the flora). Potentilla anserina is polymorphic in most features, especially in hairiness, but also in size and in degree of dissection of leaflets, epicalyx bractlets, and sepals. While most of the variation described by A. G. Blytt (1906) is taxonomically insignificant, A. Rousi (1965) found support for three northern races: subspp. anserina, egedei, and pacifica. He also suggested that P. yukonensis Hultén might qualify as a separate subspecies. This treatment follows J. Soják (1994) in accepting four northern subspecies of P. anserina, all present in North America. A. Rousi (1965) demonstrated partial interfertility between the races of Potentilla anserina, which form intermediates in all zones of contact. The distinctness of the four races, in spite of intermediates, is upheld by being partly allopatric and occupying different habitats where they are sympatric. As partly interfertile parapatric entities, they are best treated as subspecies. The vast majority of chromosome counts are tetraploid. Tetraploid plants (2n = 28) are fully fertile; hexaploids (2n = 42) are largely pollen and seed sterile; pentaploids (2n = 35) are probably occasional hybrids (S. Erlandsson 1942, 1942b; A. Rousi 1965). A. Kurtto et al. (in J. Jalas et al. 1972+, vol. 13) considered numbers above tetraploid level as cases of occasional autopolyploidy. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Potentilla pseudosericea is currently confirmed only from the central Sierra Nevada and Sweetwater and White mountains of California (B. Ertter 2008). The species is similar to P. modesta but has a more tightly strigose, silvery vestiture and more numerous and deeply incised leaflets. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 127. | FNA vol. 9, p. 209. | ||||||||||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Pentaphylloides | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Rubricaules | ||||||||||||
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Subordinate taxa | ||||||||||||||
Synonyms | Argentina anserina | |||||||||||||
Name authority | Linnaeus: Sp. Pl. 1: 495. (1753) | Rydberg: Monogr. N. Amer. Potentilleae, 98, plate 36, figs. 1–5. (1898) | ||||||||||||
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