Potentilla canadensis |
Potentilla arenosa |
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dwarf cinquefoil |
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Habit | Plants scarcely to ± tufted. | |||||
Caudex branches | thick, not columnar, not sheathed with marcescent whole leaves. |
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Stems | initially ascending to erect, soon becoming prostrate, flagelliform, not branched, eventually rooting at some nodes, (0.3–)0.5–12 dm. |
ascending to erect, (0.3–)0.8–2.5(–4.5) dm, lengths (2–)3–5 times basal leaves. |
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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. |
1.5–12(–20) cm; petiole 1–7(–15) cm, long hairs sparse to abundant, spreading to ± ascending, rarely loosely appressed, 1–2(–2.5) mm, usually stiff, sometimes weak (subsp. chamissonis), verrucose, short and/or crisped hairs absent or sparse to abundant, cottony hairs absent, glands absent or sparse; leaflets separate to ± overlapping, central obovate, 1–3.5(–4.5) × 0.5–2(–3) cm, usually petiolulate, petiolule to 5 mm, base cuneate, margins slightly revolute, distal ± 3/4 incised ± 1/2 to midvein, teeth (2–)3–4(–6) per side, ± approximate to distant, surfaces dissimilar, often strongly so, abaxial white to gray, long hairs 0.5–1.8 mm, cottony-crisped hairs ± dense, adaxial green, sometimes grayish green, long hairs sparse to abundant, short-crisped hairs sparse to abundant. |
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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–)1–2. |
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Inflorescence(s) | solitary flowers at stolon nodes. |
1–7(–15)-flowered. |
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Pedicels | (1–)2–5(–9) cm. |
1.5–5 cm in flower, to 6(–10) cm in fruit. |
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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 linear-lanceolate to lanceolate-elliptic, 2–5(–7) × 0.4–1.2(–1.5) mm, 1/4–1/2 as wide as sepals, margins usually flat, red glands absent or sparse and inconspicuous; hypanthium 3–5 mm diam.; sepals 3–6(–8) mm, apex acute; petals 4–7(–10) × 4–7(–9) mm, ± longer than sepals; filaments 0.8–1 mm, anthers 0.4 mm; carpels 28–40, apical hairs absent, styles conic-columnar, strongly papillate-swollen in proximal 1/5–1/3, 1–1.5 mm. |
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Achenes | 1.2–1.4 mm, smooth. |
1.1 mm. |
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Rootstocks | erect, stout, 0.5–2 cm. |
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2n | = 28. |
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Potentilla canadensis |
Potentilla arenosa |
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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
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AK; AB; BC; MB; NT; NU; QC; SK; YT; Eurasia |
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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.) |
Subspecies 2 (2 in the flora). The name Potentilla arenosa is now used for most arctic and subarctic plants previously treated as P. hookeriana or P. nivea subsp. hookeriana (Lehmann) Hiitonen. As noted by J. Soják (1986), the type of P. hookeriana has quinate leaves; that name is now restricted to a Rocky Mountain species in sect. Rubricaules. The arctic and subarctic material was briefly (1989–1999) called P. nivea, as discussed under that species. Because the type of P. nivea var. arenosa and other northern Asian specimens correspond closely to the North American plants, the name P. arenosa is assigned here. The two subspecies differ only in one character, the petiole hairs, but are largely allopatric. Subspecies arenosa occurs in western and northern Greenland, northern North America (very northern in the east), and northern Asia (and perhaps northeasternmost European Russia); subsp. chamissonis occurs in southern Greenland, northeastern North America (more southern than subsp. arenosa), and northern Europe at least east to the Urals. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 134. | FNA vol. 9, p. 200. | ||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Potentilla | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Niveae | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | P. canadensis var. pumila, P. canadensis var. villosissima, P. caroliniana, P. pumila | P. nivea var. arenosa | ||||
Name authority | Linnaeus: Sp. Pl. 1: 498. (1753) | (Turczaninow) Juzepczuk: in V. L. Komarov et al., Fl. URSS 10: 137. (1941) | ||||
Web links |