Potentilla canadensis |
Potentilla thurberi |
|||||
---|---|---|---|---|---|---|
dwarf cinquefoil |
scarlet cinquefoil, Thurber's cinquefoil |
|||||
Stems | initially ascending to erect, soon becoming prostrate, flagelliform, not branched, eventually rooting at some nodes, (0.3–)0.5–12 dm. |
(2–)3–7(–10) 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. |
palmate, (2–)4–15(–30) cm; petiole (2–)3–10(–25) cm, long hairs sparse to common, spreading, 1–3.5 mm, weak, glands sparse to abundant, sometimes absent; leaflets 5(–7), at tip of leaf axis, central one (1–)2–6(–8) × (0.5–)1–2.5(–4) cm, petiolules 0(–10) mm, distal 3/4 to whole margin incised 1/5–1/4 to midvein, teeth (4–)7–15(–19) per side (sometimes secondarily toothed), (1–)2–3(–5) mm, teeth apex acute to ± obtuse, surfaces slightly to strongly dissimilar, abaxial pale green to white, straight hairs sparse to abundant, often dense on veins, 0.5–3 mm, cottony hairs absent or sparse to dense, glands ± sparse or absent, sometimes obscured, adaxial green, straight hairs sparse to abundant, 0.2–1 mm, cottony hairs absent, glands ± sparse or absent. |
||||
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. |
stipules usually toothed, sometimes entire. |
||||
Inflorescences | solitary flowers at stolon nodes. |
(4–)10–35-flowered. |
||||
Pedicels | (1–)2–5(–9) cm. |
0.5–4 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 narrowly to broadly lanceolate-elliptic (rarely toothed or lobed), 4–9(–14) × (1–)1.5–2 mm; sepals 4–10(–15) mm, apex acute to acuminate; petals ± dark reddish throughout, (3.5–)6–10 × 6–10 mm; filaments 1.5–3 mm, anthers 0.8–1 mm; carpels 30–70, styles 2.5–3.5 mm. |
||||
Achenes | 1.2–1.4 mm, smooth. |
1.5 mm, ± rugose. |
||||
Rootstocks | erect, stout, 0.5–2 cm. |
|||||
2n | = 28. |
|||||
Potentilla canadensis |
Potentilla thurberi |
|||||
Phenology | Flowering late Mar–early Jun. | |||||
Habitat | Dry flats and slopes in lawns, pastures, roadsides, cherty slopes, dry meadows, edges of oak and conifer woodlands, often on acidic soil | |||||
Elevation | 0–1500 m (0–4900 ft) | |||||
Distribution |
CT; DC; DE; KY; MA; MD; ME; MO; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WV; NS; ON
|
AZ; NM; nw Mexico
|
||||
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.) |
Varieties 2 (2 in the flora). The abaxially white-cottony leaflets of var. atrorubens usually make it easily distinguished from var. thurberi, which lacks cottony hairs and is usually less hairy in general. The two varieties sometimes occur together and intermediates between the extremes are common. The degree of glandularity and the lengths of the central leaflets are greater in the southern populations of both varieties. The glands are less widely distributed on the plants northward and are fewer in northern Arizona and New Mexico. Leaflets are shorter and broader north of Graham County, Arizona, and Otero County, New Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||
Key |
|
|||||
Source | FNA vol. 9, p. 134. | FNA vol. 9, p. 149. | ||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Potentilla | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Rubrae | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | P. canadensis var. pumila, P. canadensis var. villosissima, P. caroliniana, P. pumila | |||||
Name authority | Linnaeus: Sp. Pl. 1: 498. (1753) | A. Gray: Pl. Nov. Thurb., 318. (1854) | ||||
Web links |