Potentilla anserina |
Potentilla flabellifolia |
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common silverweed, Pacific cinquefoil, silver weed cinquefoil, silverweed |
fan-foil, fan-leaf cinquefoil, fanleaf or fanfoil or Mount Rainier cinquefoil, fringe-leaf cinquefoil, high mountain cinquefoil |
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Habit | Plants ± openly matted; caudex branches short to elongate, ± stout. | |||||||||||||
Stems | ascending to erect, (0.3–)1–3 dm, lengths 2 times basal leaves. |
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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). |
2-ranked, ternate, (1–)3–12(–20) cm; stipules: apex rounded; petiole (0.5–)1–15(–18) cm, hairs and glands usually absent; leaflets 3, central widely obovate to flabellate, (0.5–)1–5 × (0.4–)1–3(–3.5) cm, petiolule 0–5(–10) mm, margins flat, not or shallowly lobed (sinuses extending less than 1/2 to midvein), distal 1/2–3/4 usually unevenly incised 1/4–1/2 to midvein, teeth 3–7 per side, often secondarily toothed, surfaces similar, green, hairs absent or sparse, rarely common, 0.5–1 mm, glands absent or sparse. |
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Inflorescences | 1–6-flowered. |
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Pedicels | straight, 0.3–4.5(–5) cm, not much longer in fruit than in flower. |
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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 often toothed or 2-lobed, elliptic to oval, 3.5–7 × (1–)1.5–3 mm, margins flat; hypanthium 3–7 mm diam.; sepals 4–8 mm, apex acute to obtuse; petals dark yellow, (5–)6–10(–12) × (3–)5–10 mm; filaments 1.5–3 mm, anthers 0.6–1.5 mm; carpels 20–50, styles filiform, not or slightly papillate-swollen proximally, 1.6–2.5 mm. |
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Achenes | 2 mm. |
1.2–1.5 mm. |
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2n | = 28. |
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Potentilla anserina |
Potentilla flabellifolia |
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Phenology | Flowering summer. | |||||||||||||
Habitat | Moist to wet or swampy, sometimes dry, stream banks, lakeshores, meadows, in conifer woodlands, subalpine and alpine grassy, rocky slopes, near or above timberline | |||||||||||||
Elevation | 1000–3700 m (3300–12100 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; ID; MT; NV; OR; WA; WY; AB; BC
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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 flabellifolia is found in the mountains from southern British Columbia, southwestern Alberta, and southwestern Montana to the southern Sierra Nevada of California. (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. 190. | ||||||||||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Pentaphylloides | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Aureae | ||||||||||||
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Subordinate taxa | ||||||||||||||
Synonyms | Argentina anserina | |||||||||||||
Name authority | Linnaeus: Sp. Pl. 1: 495. (1753) | Hooker ex Torrey & A. Gray: Fl. N. Amer. 1: 442. (1840) | ||||||||||||
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