Potentilla canadensis |
Potentilla holmgrenii |
|
---|---|---|
dwarf cinquefoil |
Holmgren's cinquefoil |
|
Habit | Plants densely tufted to cushion-forming. | |
Caudex branches | stout, columnar, at least partly sheathed with marcescent whole leaves. |
|
Stems | initially ascending to erect, soon becoming prostrate, flagelliform, not branched, eventually rooting at some nodes, (0.3–)0.5–12 dm. |
ascending, 0.2–0.8 dm, lengths 1.5–2.5 times basal leaves. |
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. |
1.5–4 cm; petiole 0.5–2 cm, long hairs absent or sparse to common (less so than cottony hairs), ± appressed, 1–2 mm, soft, smooth, cottony hairs dense, other hairs and glands absent, sparse, or obscured; leaflets touching to overlapping, central broadly elliptic to obovate, 0.7–1.1 × 0.5–0.6 cm, sessile or short-petiolulate, petiolule to 1 mm, base cuneate, margins revolute, distal 1/2–3/4 incised ± 1/2 to midvein, teeth 2–4 per side, approximate, surfaces ± dissimilar, abaxial white to grayish white, long hairs 1 mm, cottony-crisped hairs dense, adaxial grayish green to grayish white, long and short-crisped hairs abundant to dense. |
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. |
0–1. |
Inflorescences | solitary flowers at stolon nodes. |
1–2(–3)-flowered. |
Pedicels | (1–)2–5(–9) cm. |
0.4–0.7 cm in flower, to 2 cm in fruit. |
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 lanceolate to narrowly elliptic, 2–2.2 × 0.6–0.9 mm, 1/4–1/2 as wide as sepals, margins flat, red glands absent; hypanthium 1.8–2.2 mm diam.; sepals 3–3.5 mm, apex subacute; petals 4–5 × 2.5–4 mm, longer than sepals; filaments 1–1.5 mm, anthers 0.5 mm; carpels 30–40, apical hairs absent, styles narrowly columnar, not or ± papillate-swollen in proximal 1/5 or less, 1.2–1.4 mm. |
Achenes | 1.2–1.4 mm, smooth. |
1.1–1.4 mm. |
Rootstocks | erect, stout, 0.5–2 cm. |
|
2n | = 28. |
|
Potentilla canadensis |
Potentilla holmgrenii |
|
Phenology | Flowering late Mar–early Jun. | Flowering summer. |
Habitat | Dry flats and slopes in lawns, pastures, roadsides, cherty slopes, dry meadows, edges of oak and conifer woodlands, often on acidic soil | Wind-swept ridges, fellfields, rocky slopes |
Elevation | 0–1500 m (0–4900 ft) | 3300–4500 m (10800–14800 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 holmgrenii is known only from the Schell Creek and Snake ranges, Nevada, and Deep Creek Range, Utah. In addition to characteristics given in the key, lateral leaflets and leaflet teeth of P. holmgrenii are directed more forward than in P. nivea, leaflets are thicker and more densely hairy, and the terminal tooth is often orbiculate and frequently overlapped by the adjacent pair of lateral teeth. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 134. | FNA vol. 9, p. 199. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Potentilla | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Niveae |
Sibling taxa | ||
Synonyms | P. canadensis var. pumila, P. canadensis var. villosissima, P. caroliniana, P. pumila | |
Name authority | Linnaeus: Sp. Pl. 1: 498. (1753) | D. F. Murray & Elven: J. Bot. Res. Inst. Texas 1: 811, figs. 1, 2. (2007) |
Web links |