Potentilla hippiana |
Potentilla arenosa |
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Hipp's cinquefoil, horse cinquefoil, potentille de Hipp, woolly 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 | (0.3–)2–4(–5) dm, lengths (1–)2–4 times basal leaves. |
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 | pinnate to subpinnate, (3–)5–15(–25) cm; petiole 1–10(–15) cm, long hairs abundant to dense, tightly appressed, 1–2.5 mm, stiff, short hairs absent or obscured, crisped-cottony hairs absent or sparse to common, glands absent or obscured; leaflets not conduplicate, lateral ones evenly (to unevenly in argyrea phase) paired, (2–)3–6(–7) per side on distal (1/6–)1/5–1/2 of leaf axis, distal pairs ± decurrent, often confluent with terminal leaflet, larger leaflets oblanceolate or narrowly obovate to oblong, 1–5(–6) × 0.3–1.5 cm, distal (2/3–)3/4 to whole margin incised 1/2 or less (rarely more) to midvein, teeth (5–)7–12(–18) per side, 1–4 mm, surfaces ± to strongly dissimilar, abaxial white, long hairs abundant (mostly on, but not limited to, veins), 1–2 mm, stiff, short hairs absent or obscured, crisped-cottony hairs abundant to dense, glands absent or obscured, adaxial green to grayish, long hairs sparse to common, rarely absent, short or crisped to, sometimes, cottony hairs absent or sparse to common, glands sparse. |
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 | 1–2(–3). |
(0–)1–2. |
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Inflorescence(s) | 10–30-flowered. |
1–7(–15)-flowered. |
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Pedicels | 0.3–3(–5) cm. |
1.5–5 cm in flower, to 6(–10) cm in fruit. |
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Flowers | epicalyx bractlets narrowly elliptic to lanceolate, rarely linear, 2–5 × 0.5–1.5 mm, (1/2–)2/3 as long as sepals, abaxial vestiture similar to or ± sparser than sepals, usually not glabrescent, straight hairs ± abundant, crisped to sometimes ± cottony hairs absent or sparse to abundant; hypanthium 3–7 mm diam.; sepals 4–5.5(–6.5) mm, apex acute to acuminate; petals 4–8 × 4–7 mm; filaments 0.5–2.5 mm, anthers 0.6–1.1 mm; carpels (5–)10–30, styles 1.7–2.5 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 | 1.4–1.8 mm, smooth to faintly rugose. |
1.1 mm. |
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2n | = 42, 70, 77, 84, 98. |
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Potentilla hippiana |
Potentilla arenosa |
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Phenology | Flowering summer. | |||||
Habitat | Dry grasslands and meadows, in aspen and conifer woodlands or alpine tundra, disturbed sites | |||||
Elevation | 500–3400 m (1600–11200 ft) | |||||
Distribution |
AZ; CO; ID; MI; MN; MT; ND; NE; NM; NV; SD; UT; WY; AB; BC; MB; NS; NT; ON; QC; SK
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AK; AB; BC; MB; NT; NU; QC; SK; YT; Eurasia |
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Discussion | Potentilla hippiana is most common and distinctive in the Colorado Plateau and southern Rocky Mountains, with outliers in the mountains of Arizona, Nevada, and New Mexico. Occurrences are more scattered in the northern Rocky Mountains and Great Plains, where intergradation with P. effusa is common. Among these intermediates are the argyrea phase and the single report from Idaho (B. C. Johnston 1980). Potentilla hippiana is probably adventive in Nova Scotia, eastern Ontario, Quebec, and Michigan, and possibly the Northwest Territories. The reported occurrence in central Alaska (E. Hultén 1968) is based on a specimen of P. pensylvanica (CAN). Significant variation exists throughout the range of Potentilla hippiana, including dwarfism, leaf division, leaflet dissection, adaxial leaflet vestiture, and pedicel length. Some of this variation might merit taxonomic recognition upon further analysis, especially if correlated with ploidy level (6x through 12x). At present, the differences used to distinguish var. argyrea are not found to be sufficiently correlated with distribution to merit formal taxonomic recognition. Complicating the infraspecific variation is a tendency for Potentilla hippiana to intergrade with other species, in particular P. effusa. Beyond sect. Leucophyllae, the frequency of hybrids with P. pulcherrima blurs the distinction between the two species; P. gracilis var. hippianoides S. L. Welsh & N. D. Atwood is probably one of the resultant intermediates. (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. 162. | FNA vol. 9, p. 200. | ||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Leucophyllae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Niveae | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | P. leucophylla, P. argyrea, P. effusa var. argyrea, P. hippiana var. argyrea, P. hippiana var. diffusa, P. propinqua | P. nivea var. arenosa | ||||
Name authority | Lehmann: Nov. Stirp. Pug. 2: 7. (1830) — not Pallas 1773 | (Turczaninow) Juzepczuk: in V. L. Komarov et al., Fl. URSS 10: 137. (1941) | ||||
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