Potentilla anserina |
Potentilla johnstonii |
|||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
common silverweed, Pacific cinquefoil, silver weed cinquefoil, silverweed |
sagebrush cinquefoil |
|||||||||||||
Stems | 0.4–2 dm, lengths 2 times basal leaves. |
|||||||||||||
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, 3–8(–13) cm; petiole 1.5–5(–8) cm, straight hairs abundant, ± appressed, 1–2 mm, stiff, cottony hairs absent, glands sparse to abundant; leaflets (3–)5–7(–9), on tip or at least less than distal 1/10 of leaf axis, separate to slightly overlapping, proximal pair separated from others by 0–1 mm of leaf axis, central leaflets narrowly cuneate to oblanceolate, 1–3(–4) × 0.3–0.7 cm, petiolule 1 mm, distal 1/4 or less of margins incised 1/3–2/3 to midvein, teeth 1(–3) per side, separate, 1–2(–4) mm, surfaces similar, green to grayish, straight hairs sparse to common, appressed, 1–1.5(–2) mm, stiff (sometimes softer and wavy), cottony hairs absent, glands sparse to abundant. |
||||||||||||
Inflorescences | 4–11-flowered. |
|||||||||||||
Pedicels | 0.7–2(–4) cm. |
|||||||||||||
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, 2–4 × 1 mm; hypanthium 3–4(–6) mm diam.; sepals 3–4.5 mm, apex acute to obtuse; petals 5–7 × 3–5 mm; filaments 1–2.5 mm, anthers 0.6–0.8 mm; carpels 3–10, styles 2–2.5 mm. |
||||||||||||
Achenes | 2 mm. |
2.5 mm, smooth to slightly rugose. |
||||||||||||
Potentilla anserina |
Potentilla johnstonii |
|||||||||||||
Phenology | Flowering summer. | |||||||||||||
Habitat | Rocky slopes in pinyon-juniper woodlands, with Artemisia | |||||||||||||
Elevation | 2300–2500 m (7500–8200 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
|
NV |
||||||||||||
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.) |
Of conservation concern. Potentilla johnstonii occurs only in the Quinn Canyon Range in Nye County. Its distinctiveness was first noted by B. C. Johnston (1980), who treated it as a variety of P. concinna using the unpublished epithet curvata. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||||||||||
Key |
|
|||||||||||||
Source | FNA vol. 9, p. 127. | FNA vol. 9, p. 182. | ||||||||||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Pentaphylloides | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Concinnae | ||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Synonyms | Argentina anserina | |||||||||||||
Name authority | Linnaeus: Sp. Pl. 1: 495. (1753) | Soják: Thaiszia 16: 97. (2007) | ||||||||||||
Web links |
|