Potentilla anserina |
Potentilla wheeleri |
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common silverweed, Pacific cinquefoil, silver weed cinquefoil, silverweed |
Kern cinquefoil, Wheeler's cinquefoil |
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Stems | 0.2–2.5 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). |
palmate, 1.5–9.5 cm; petiole 1–7 cm, long hairs abundant to dense, spreading to appressed, 1–2 mm, weak to stiff, glands ± abundant; leaflets 5, central cuneate-elliptic to obovate, 0.5–2.5 × 0.3–1.5 cm, scarcely to distinctly petiolulate, distal 1/3 of margins evenly incised ± 1/4 to midvein, teeth 2–4(–5) per side, surfaces gray-green, long hairs abundant to dense, 1–1.5 mm, glands ± abundant, sometimes obscured. |
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Inflorescences | 1–20-flowered. |
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Pedicels | 0.5–1.5 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 lanceolate to ovate-elliptic, 1–3.5 × 1–1.5 mm; hypanthium 2–4 mm diam.; sepals 2–5 mm, apex ± acute; petals ± paler abaxially, bright yellow adaxially, ± obcordate, 3–6 × 2–5 mm; filaments 1–2 mm, anthers 0.5 mm; carpels ca. 20, styles (1.2–)1.5–2 mm. |
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Achenes | 2 mm. |
1–1.5 mm, lightly rugose. |
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Short | hairs not well differentiated from long hairs, absent or sparse throughout. |
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Potentilla anserina |
Potentilla wheeleri |
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Phenology | Flowering May–Sep. | |||||||||||||
Habitat | Sandy flats, streamsides, lake margins, open conifer woodlands, alpine fellfields | |||||||||||||
Elevation | 1800–3500 m (5900–11500 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 wheeleri is found in the southern Sierra Nevada and San Bernardino Mountains of southern California. Compact plants on the summit of Mount San Gorgonio, described by Jepson as var. paupercula, show no consistent difference to justify their taxonomic segregation. Variety viscidula Rydberg has been misapplied to Arizona populations now called P. rhyolitica. Plants identified as P. wheeleri (excluding P. rimicola) from the Sierra San Pedro Mártir (Baja California) stand as a distinct species, P. luteosericea Rydberg (= P. pinetorum Wiggins). (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. 185. | ||||||||||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Pentaphylloides | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Subviscosae | ||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Synonyms | Argentina anserina | P. wheeleri var. paupercula | ||||||||||||
Name authority | Linnaeus: Sp. Pl. 1: 495. (1753) | S. Watson: Proc. Amer. Acad. Arts 11: 148. (1876) | ||||||||||||
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