Potentilla canadensis |
Potentilla cottamii |
|
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dwarf cinquefoil |
Cottam's cinquefoil, pilot range cinquefoil |
|
Stems | initially ascending to erect, soon becoming prostrate, flagelliform, not branched, eventually rooting at some nodes, (0.3–)0.5–12 dm. |
0.4–1.7 dm. |
Basal leaves | ± persistent, usually palmate, 2–9(–11) cm; petiole 1–7(–8) cm, long hairs abundant to dense, appressed to spreading, 1.5–3 mm, mostly ± weak, glands absent or sparse; leaflets (3–)5(–7), central mostly ± obovate to cuneate, sometimes narrowly so, (0.5–)1–4(–6) × (0.5–)0.8–2(–3) cm, distal 1/2 of margin incised 1/4–1/3 to midvein, teeth 2–7 per side, surfaces similar to ± dissimilar, abaxial green to silvery white, sparsely to densely hairy, adaxial green, sparsely to moderately hairy. |
ternate, (1.5–)2–6(–8) cm; petiole 0.8–5(–7) cm, long hairs sparse to abundant, usually ± spreading, sometimes ascending, 0.5–1 mm, weak to ± stiff, glands sparse to common; leaflets 3, central obovate-cuneate, (0.2–)0.5–1(–1.5) × 0.2–1 cm, scarcely petiolulate, distal 1/2–2/3 of margins evenly incised 1/3–1/2 to midvein, teeth (1–)2–3(–4) per side, surfaces green, long hairs sparse to common, 0.5–1 mm, glands sparse to abundant. |
Cauline leaves | 0–1 proximal to 1st flowering node, not fully expanded at anthesis, usually palmate, 2–7(–9) cm; petiole (0.5–)1–6(–7.5) cm; leaflets (3–)5, ± resembling those of basal leaves, apex rounded to obtuse. |
|
Inflorescences | solitary flowers at stolon nodes. |
1–4-flowered. |
Pedicels | (1–)2–5(–9) cm. |
0.5–2(–4) cm. |
Flowers | 5-merous; epicalyx bractlets linear to lanceolate-elliptic, (2–)3–5(–6) × 0.8–1.5 mm, slightly smaller than to ± equal to sepals; hypanthium 2.5–5 mm diam.; sepals (2–)3–5(–6) mm, apex acute; petals 4–6(–8) × 3.5–6.5(–8) mm, apex rounded to slightly retuse; stamens ca. 20, filaments 0.5–2 mm, anthers 0.4–1 mm; carpels 20–40, styles 0.8–1.4 mm. |
epicalyx bractlets sometimes paired, narrowly elliptic, 1.5–2(–2.5) × 0.5–1 mm 1/2–3/4 as long as sepals; hypanthium 2–3 mm diam.; sepals 2.5–4 mm, apex broadly acute; petals ± paler abaxially, bright yellow adaxially, ± obcordate to broadly obovate, (2–)3–4 × 2–3 mm; filaments 1–1.5 mm, anthers 0.3–0.5 mm; carpels 10–25, styles 1–1.5 mm. |
Achenes | 1.2–1.4 mm, smooth. |
1.3 mm, smooth to lightly rugose. |
Rootstocks | erect, stout, 0.5–2 cm. |
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Short | hairs not well differentiated from long hairs, absent or sparse throughout. |
|
2n | = 28. |
|
Potentilla canadensis |
Potentilla cottamii |
|
Phenology | Flowering late Mar–early Jun. | Flowering Jun–Aug. |
Habitat | Dry flats and slopes in lawns, pastures, roadsides, cherty slopes, dry meadows, edges of oak and conifer woodlands, often on acidic soil | Protected rock crevices, near vertical faces of quartzite and granite |
Elevation | 0–1500 m (0–4900 ft) | 2200–3600 m (7200–11800 ft) |
Distribution |
CT; DC; DE; KY; MA; MD; ME; MO; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WV; NS; ON
|
NV; UT |
Discussion | A cream-colored form (ochroleuca) was described from a now-obliterated site in Massachusetts (M. L. Fernald 1931). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Potentilla cottamii is known only from the Pilot Range, Elko County, Nevada, and in northwestern Utah from the Deep Creek, Raft River, and Stansbury mountains. Plants of P. cottamii can form dense clumps to 4 dm across. Except for the short style, which led Holmgren to associate the species with P. hyparctica and P. robbinsiana in sect. Aureae, P. cottamii fits well in sect. Subviscosae. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 134. | FNA vol. 9, p. 187. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Potentilla | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Subviscosae |
Sibling taxa | ||
Synonyms | P. canadensis var. pumila, P. canadensis var. villosissima, P. caroliniana, P. pumila | |
Name authority | Linnaeus: Sp. Pl. 1: 498. (1753) | N. H. Holmgren: Brittonia 39: 340, fig. 1. (1987) |
Web links |