Potentilla canadensis |
Potentilla macounii |
|
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dwarf cinquefoil |
Macoun's cinquefoil |
|
Stems | initially ascending to erect, soon becoming prostrate, flagelliform, not branched, eventually rooting at some nodes, (0.3–)0.5–12 dm. |
0.4–1.5(–2) dm, lengths 2 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. |
subpinnate to pinnate, usually at least 2 pairs of leaflets separate from terminal leaflets, distal leaflets often confluent, 2–7 cm; petiole 1–4(–8) cm, straight hairs abundant, ± appressed to ascending, 1–2 mm, stiff to weak, cottony hairs sometimes present, glands absent or obscured; leaflets 5–9(–11), on distal 1/5–1/2 of leaf axis, strongly overlapping, proximal pair separate from others by 1–5 mm of leaf axis, central leaflets oblanceolate to obovate, sometimes lobed, (0.5–)1–1.5 × 0.5–1 cm, petiolules 0–1 mm, distal 2/3 of margins incised 1/2+ to midvein, teeth 2–5 per side, touching, 1–3 mm, surfaces ± dissimilar, abaxial white, straight hairs ± abundant, ± appressed, 1–1.5 mm, weak to stiff, cottony hairs ± dense, glands absent or obscured, adaxial greenish gray, straight hairs sparse to abundant, usually appressed, sometimes ascending, 1 mm, usually ± stiff, sometimes soft, cottony hairs sparse, glands obscured. |
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–)3–6(–10)-flowered. |
Pedicels | (1–)2–5(–9) cm. |
0.8–2 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 lanceolate to ovate-elliptic, 2.5–4 × 0.8–1.5 mm; hypanthium 3–4 mm diam.; sepals (3–)3.5–5.5(–6) mm, apex ± acute; petals 6–7 × 5–7 mm; filaments 1.5–3 mm, anthers 0.8–1 mm; carpels 15–20, styles 2–2.5 mm. |
Achenes | 1.2–1.4 mm, smooth. |
1.5–2 mm, smooth. |
Rootstocks | erect, stout, 0.5–2 cm. |
|
2n | = 28. |
|
Potentilla canadensis |
Potentilla macounii |
|
Phenology | Flowering late Mar–early Jun. | Flowering early summer. |
Habitat | Dry flats and slopes in lawns, pastures, roadsides, cherty slopes, dry meadows, edges of oak and conifer woodlands, often on acidic soil | Rocky slopes, outcrops, gravel banks, prairies |
Elevation | 0–1500 m (0–4900 ft) | 1200–2200 m (3900–7200 ft) |
Distribution |
CT; DC; DE; KY; MA; MD; ME; MO; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WV; NS; ON
|
MT; AB |
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 macounii differs from other species in sect. Concinnae in the combination of subpinnate leaves, with at least two proximal pairs of leaflets separated from the terminal leaflets, and in having somewhat softer hairs. It occurs on the eastern slopes of the Rocky Mountains in southwestern Alberta (where of conservation concern) and in western Montana. Some problematic collections from the Absaroka Range in western Wyoming are most comparable to P. macounii, but have softer vestiture and somewhat larger, less divided, more subpalmate leaves. If these Wyoming populations were included in P. macounii, the upper elevation range would be 3300 m. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 134. | FNA vol. 9, p. 180. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Potentilla | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Concinnae |
Sibling taxa | ||
Synonyms | P. canadensis var. pumila, P. canadensis var. villosissima, P. caroliniana, P. pumila | P. concinna var. macounii |
Name authority | Linnaeus: Sp. Pl. 1: 498. (1753) | Rydberg: Monogr. N. Amer. Potentilleae, 101, plate 41, figs. 1, 2. (1898) |
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