Potentilla millefolia |
Potentilla rivalis |
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cut-leaf cinquefoil, feather cinquefoil, feather or many-leaf or Klamath cinquefoil, many leaf cinquefoil |
brook cinquefoil, brook or river cinquefoil, river cinquefoil, streambank cinquefoil |
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Habit | Plants ± rosetted; taproots fleshy-thickened. | |
Stems | usually prostrate, sometimes ± decumbent, 0.4–2(–3) dm, lengths 1–2 times basal leaves. |
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 | pinnate with distal leaflets ± confluent, 2–15(–20) × 1–3 cm; petiole 0.5–2(–3) cm, straight hairs sparse to abundant, appressed to spreading, 0.5–1.5 mm, stiff, cottony hairs absent, glands absent or sparse; primary lateral leaflets (3–)5–13 per side, on distal 2/3–3/4+ of leaf axis, separate to overlapping, largest ones cuneate to flabellate, 0.5–1.5(–2) × 0.5–2 cm, distal 2/3 to whole margin palmately or unevenly, rarely pinnately, incised 2/3 to completely to midvein, ultimate teeth or segments (1–)2–10, linear to broadly oblanceolate, 2–10 × (0.5–)1–2 mm, apical tufts to 1 mm, surfaces green to grayish green, not glaucous, straight hairs sparse to abundant, appressed to spreading, 0.5–1.5(–2) mm, stiff, cottony hairs absent, glands sparse to common. |
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Cauline leaves | (0–)1–2. |
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Inflorescences | 3–6(–10)-flowered, loosely cymose, sometimes racemiform. |
(5–)20–100+-flowered. |
Pedicels | (0.5–)1–2(–4.5) cm, ± recurved in fruit. |
0.2–1(–2) cm. |
Flowers | epicalyx bractlets ± elliptic, 2–4(–6) × 1–2(–2.5) mm; hypanthium 3–6 mm diam.; sepals 4–6(–8) mm, apex acute; petals 4–8(–10) × 3–7(–9) mm; filaments 2–3.5 mm, anthers 0.7–1 mm; carpels 10–30, styles (1.5–)2–3 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 | 1.5–2 mm, smooth, often ± carunculate. |
yellowish, 0.7–0.9 mm, ± smooth, without a corky protuberance. |
2n | = 14, 70. |
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Potentilla millefolia |
Potentilla rivalis |
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Phenology | Flowering spring–summer. | Flowering spring–summer. |
Habitat | Vernally to permanently wet meadows, moist openings in conifer forests and sagebrush, alkaline flats | Moist meadows, stream banks, lakeshores, gravel bars in flood plains, drying marshes, open areas in river-bottom forests |
Elevation | 700–2200 m (2300–7200 ft) | 200–2400 m (700–7900 ft) |
Distribution |
CA; NV; OR
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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 millefolia occurs from central Oregon to the east side of the Sierra Nevada of California, with a disjunct occurrence on the alkaline flats of Reese River Valley, Nevada. Significant variation occurs in vestiture type, leaflet dissection, and flower size, but with minimal geographic correlation. The most distinctive variant, represented by the type of P. klamathensis, has relatively long, slender, spreading, pustule-based hairs, often intermixed with shorter hairs. This vestiture type does not appear to be correlated with any other characters or geographic distribution and may vary within a population. (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. 174. | FNA vol. 9, p. 139. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Multijugae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Rivales |
Sibling taxa | ||
Synonyms | P. klamathensis, P. millefolia var. klamathensis, P. plattensis var. klamathensis, P. plattensis var. millefolia | P. millegrana, P. pentandra, P. rivalis var. millegrana, P. rivalis var. pentandra |
Name authority | Rydberg: Bull. Torrey Bot. Club 23: 433, plate 277, figs. 1–5. (1896) | Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 437. (1840) |
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