Potentilla wheeleri |
Potentilla rivalis |
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Kern cinquefoil, Wheeler's cinquefoil |
brook cinquefoil, brook or river cinquefoil, river cinquefoil, streambank cinquefoil |
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Stems | 0.2–2.5 dm. |
decumbent to erect, sometimes prostrate, (0.5–)1–4(–7) dm, hairs at base not stiff, not tubercle-based, glands absent or sparse, inconspicuous. |
Leaves | ternate, palmate, or subpalmate (with distal leaflets ± confluent), basal 3–15(–25) cm, cauline 2–7(–12) cm; petiole: basal 1–9(–16) cm, cauline 0.5–4(–8) cm, long hairs usually common to abundant, ascending to spreading, 0.5–1.5 mm, usually ± weak, ± crisped hairs common to abundant, glands absent or sparse, inconspicuous; leaflets 3–5(–7), at tip to distal 1/5 (basal) or 1/2 (cauline) of leaf axis, separate to ± overlapping, largest ones oblanceolate-elliptic to obovate, (0.5–)1–5(–6) × 0.5–2(–2.5) cm, distal 1/2–3/4 of margin evenly to unevenly incised 1/3–1/2 to midvein, sometimes cleft nearly to base, teeth 3–8 per side, surfaces moderately to abundantly hairy, glands absent or sparse. |
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Basal leaves | palmate, 1.5–9.5 cm; petiole 1–7 cm, long hairs abundant to dense, spreading to appressed, 1–2 mm, weak to stiff, glands ± abundant; leaflets 5, central cuneate-elliptic to obovate, 0.5–2.5 × 0.3–1.5 cm, scarcely to distinctly petiolulate, distal 1/3 of margins evenly incised ± 1/4 to midvein, teeth 2–4(–5) per side, surfaces gray-green, long hairs abundant to dense, 1–1.5 mm, glands ± abundant, sometimes obscured. |
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Inflorescences | 1–20-flowered. |
(5–)20–100+-flowered. |
Pedicels | 0.5–1.5 cm. |
0.2–1(–2) cm. |
Flowers | epicalyx bractlets lanceolate to ovate-elliptic, 1–3.5 × 1–1.5 mm; hypanthium 2–4 mm diam.; sepals 2–5 mm, apex ± acute; petals ± paler abaxially, bright yellow adaxially, ± obcordate, 3–6 × 2–5 mm; filaments 1–2 mm, anthers 0.5 mm; carpels ca. 20, styles (1.2–)1.5–2 mm. |
epicalyx bractlets narrowly elliptic to ovate, (1.5–)2–4(–6) × 0.8–1.5 mm; hypanthium (2–)3–5 mm diam.; sepals 3–5 mm, apex broadly acute to obtuse; petals pale yellow to yellow, broadly oblong-obovate, 1.5–2 × 1 mm; stamens (5–)10(–15), filaments 0.4–0.9 mm, anthers 0.2–0.3 mm; carpels 40–100, styles 0.5–0.6 mm. |
Achenes | 1–1.5 mm, lightly rugose. |
yellowish, 0.7–0.9 mm, ± smooth, without a corky protuberance. |
Short | hairs not well differentiated from long hairs, absent or sparse throughout. |
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2n | = 14, 70. |
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Potentilla wheeleri |
Potentilla rivalis |
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Phenology | Flowering May–Sep. | Flowering spring–summer. |
Habitat | Sandy flats, streamsides, lake margins, open conifer woodlands, alpine fellfields | Moist meadows, stream banks, lakeshores, gravel bars in flood plains, drying marshes, open areas in river-bottom forests |
Elevation | 1800–3500 m (5900–11500 ft) | 200–2400 m (700–7900 ft) |
Distribution |
CA
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AZ; CA; CO; IA; ID; IL; KS; MA; MD; ME; MN; MO; MT; ND; NE; NM; NV; NY; OK; OR; SD; TX; UT; VA; WA; WI; WY; AB; BC; MB; ON; SK; Mexico (Baja California)
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Discussion | Potentilla wheeleri is found in the southern Sierra Nevada and San Bernardino Mountains of southern California. Compact plants on the summit of Mount San Gorgonio, described by Jepson as var. paupercula, show no consistent difference to justify their taxonomic segregation. Variety viscidula Rydberg has been misapplied to Arizona populations now called P. rhyolitica. Plants identified as P. wheeleri (excluding P. rimicola) from the Sierra San Pedro Mártir (Baja California) stand as a distinct species, P. luteosericea Rydberg (= P. pinetorum Wiggins). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Potentilla rivalis is most abundant in central and western North America; reports of occurrences in more eastern states (including those listed here) need confirming, as P. rivalis and P. norvegica often have been confused. Potentilla leucocarpa Rydberg was provided as a superfluous replacement name for P. millegrana; specimens annotated by Rydberg with this name include both P. biennis and P. rivalis. Potentilla rivalis is sometimes divided into three species or varieties (for example, H. J. Scoggan 1978–1979). In a strict sense, var. rivalis has subpalmately compound (5-foliate) leaves. Variety milligrana, the most common phase, has 3-foliate leaves. Plants with both 3- and 5-foliolate leaves are var. pentandra, which also tends to have five stamens, though this latter character is not correlated with the leaf features. On the Great Plains, where var. pentandra is confined, all three expressions are often found in a single population (R. L. McGregor 1986b). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 185. | FNA vol. 9, p. 139. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Subviscosae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Rivales |
Sibling taxa | ||
Synonyms | P. wheeleri var. paupercula | P. millegrana, P. pentandra, P. rivalis var. millegrana, P. rivalis var. pentandra |
Name authority | S. Watson: Proc. Amer. Acad. Arts 11: 148. (1876) | Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 437. (1840) |
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