Potentilla rivalis |
Potentilla stipularis |
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brook cinquefoil, brook or river cinquefoil, river cinquefoil, streambank cinquefoil |
stipulate cinquefoil, stipulated cinquefoil |
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Glands | mostly absent. |
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Stems | decumbent to erect, sometimes prostrate, (0.5–)1–4(–7) dm, hairs at base not stiff, not tubercle-based, glands absent or sparse, inconspicuous. |
(0.2–)1–2.5(–3.5) dm. |
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 | 3–7(–10) cm; petiole 2–5(–7.5) cm, hairs absent or sparse, appressed to spreading, 0.5–0.8 mm, stiff, glands absent or nearly so; leaflets 7–11, central one oblanceolate-elliptic, 1–2(–3) × 0.3–0.8 cm, distal 1/4 or less of margin incised less than 1/10(–1/4) to midvein, teeth 1–2(–5) per side, surfaces similar, abaxial pale green to reddish, often glaucous, hairs absent or sparse to common on primary veins, appressed to ascending, 0.6–1 mm, stiff, adaxial green or reddish, glabrous or nearly so. |
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Cauline leaves | 1–3; stipules fused with all or most of petiole, free portion shorter than fused portion. |
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Inflorescences | (5–)20–100+-flowered. |
2–5-flowered. |
Pedicels | 0.2–1(–2) cm. |
1–3 cm (proximalmost to 6 cm). |
Flowers | 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. |
epicalyx bractlets lanceolate to narrowly lanceolate, 3–5 × 0.7–1(–1.5) mm; hypanthium 2.5–3 mm diam.; sepals 4–6 mm, apex acute; petals (4–)6–8 × 4–6 mm; filaments 1.6–2 mm, anthers 0.4–0.6 mm; carpels 40–50, styles 0.7–0.9 mm. |
Achenes | yellowish, 0.7–0.9 mm, ± smooth, without a corky protuberance. |
1.1–1.3 mm, smooth. |
2n | = 14, 70. |
= 28 (Eurasia). |
Potentilla rivalis |
Potentilla stipularis |
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Phenology | Flowering spring–summer. | Flowering summer. |
Habitat | Moist meadows, stream banks, lakeshores, gravel bars in flood plains, drying marshes, open areas in river-bottom forests | Herb meadows, alluvial meadows and flats, open shrub thickets, Salix-Dryas tundra |
Elevation | 200–2400 m (700–7900 ft) | 10–600 m (0–2000 ft) |
Distribution |
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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AK; Greenland; Eurasia |
Discussion | 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.) |
The occurrences of Potentilla stipularis in Alaska are a continuation of the range from Asia. The six known occurrences in eastern and northeastern Greenland are disjunct (A. E. Porsild 1964) and were assigned to var. groenlandica by Sørensen, differing from Asian and Alaskan counterparts mainly in quantitative features: 9–11 leaflets, 7–11 teeth per leaflet, and not conspicuously glaucous (G. Halliday, pers. comm.). Here var. groenlandica is considered a high-arctic ecotype that provisionally is not accepted taxonomically. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 139. | FNA vol. 9, p. 147. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Rivales | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Chrysanthae |
Sibling taxa | ||
Synonyms | P. millegrana, P. pentandra, P. rivalis var. millegrana, P. rivalis var. pentandra | P. stipularis var. groenlandica |
Name authority | Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 437. (1840) | Linnaeus: Sp. Pl. 1: 498. (1753) |
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