Potentilla anserina |
Potentilla anserina subsp. anserina |
|||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
common silverweed, Pacific cinquefoil, silver weed cinquefoil, silverweed |
common silverweed, silver weed cinquefoil, silvery cinquefoil |
|||||||||||||
Stems | densely hairy. |
|||||||||||||
Leaves | horizontal to erect, 3–20 cm, rarely longer; leaflets (5–)6–11(–12) per side, overlapping, rarely separate, teeth (4–)5–8(–11+) per side, teeth apex acute to acuminate, surfaces: abaxial with long hairs common to abundant, on and between veins, cottony-crisped hairs dense, adaxial glabrous or sparsely to densely hairy. |
|||||||||||||
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). |
|||||||||||||
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). |
1–1.5(–2) cm diam.; epicalyx bractlets narrowly to broadly ovate-triangular, equal to sepals, often 2-fid or dentate; hypanthium patelliform (much wider than deep) in fruit; petals overlapping or not, elliptic to broadly elliptic; carpels (10–)20–60. |
||||||||||||
Achenes | 2 mm. |
with dorsal groove. |
||||||||||||
2n | = 28, 35, 42. |
|||||||||||||
Potentilla anserina |
Potentilla anserina subsp. anserina |
|||||||||||||
Phenology | Flowering spring–fall. | |||||||||||||
Habitat | Dry meadows, pastures, open dry pine and aspen forests, dry sandy and gravelly stream-, lake-, and seashores, sand dunes, inland alkaline habitats, dry ruderal habitats | |||||||||||||
Elevation | 0–3000 m (0–9800 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
|
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; ON; PE; QC; SK; YT; SPM; Mexico; Eurasia; Greenland; South America (Chile); Australia |
||||||||||||
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.) |
Subspecies anserina is the most widespread subspecies, occurring both on seashores and well inland. It is presumed introduced in Greenland and Alaska. A. Rousi (1965) compared American and European plants of subsp. anserina and found no consistent morphologic differences between the continents. An ecologic difference does exist: whereas the European plants are common both in coastal and inland habitats, the American plants are mainly inland. Both native and introduced plants are probably present in North America, as the European plant is a widely established, aggressive weed. Plants with a dense sericeous vestiture on both leaf surfaces (var. sericea) are especially characteristic of inland saline habitats. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||||||||||
Key |
|
|||||||||||||
Source | FNA vol. 9, p. 127. | FNA vol. 9, p. 128. | ||||||||||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Pentaphylloides | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Pentaphylloides > Potentilla anserina | ||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Synonyms | Argentina anserina | Argentina argentea, P. anserina var. sericea, P. pratincola | ||||||||||||
Name authority | Linnaeus: Sp. Pl. 1: 495. (1753) | unknown | ||||||||||||
Web links |
|
|