Potentilla rivalis
Potentilla rimicola
brook cinquefoil, brook or river cinquefoil, river cinquefoil, streambank cinquefoil
cliff cinquefoil
decumbent to erect, sometimes prostrate, (0.5–)1–4(–7) dm, hairs at base not stiff, not tubercle-based, glands absent or sparse, inconspicuous.
0.4–2(–3) dm.
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.
palmate, 3–10 cm;
petiole 1–7 cm, long hairs abundant, spreading to ascending, 1–3 mm, weak, glands abundant;
leaflets 5, central oblanceolate to broadly obovate-cuneate or nearly orbiculate, 1–3 × 0.8–2 cm, scarcely to distinctly petiolulate, distal ± 1/3 of margins evenly incised ± 1/4 to midvein, teeth 2–4 per side, surfaces green, long hairs sparse to abundant, 1 mm, glands ± abundant.
(5–)20–100+-flowered.
3–20-flowered.
0.2–1(–2) cm.
0.5–2.5(–4) cm.
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-elliptic, rarely linear, 1–2(–5) × 0.5–1.5 mm;
hypanthium 2–3.5 mm diam.;
sepals 2–4(–5) mm, apex ± acute;
petals ± paler abaxially, bright yellow adaxially, ± obcordate, (3–)4–7 × 3–6 mm;
filaments 1.5–2.5 mm, anthers 0.5–1 mm;
carpels 5–20, styles 1.5–2.5 mm.
yellowish, 0.7–0.9 mm, ± smooth, without a corky protuberance.
1.5 mm, smooth to faintly rugose.
hairs not well differentiated from long hairs, absent or sparse throughout.
= 14, 70.
Potentilla rivalis
Potentilla rimicola
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.)
Of conservation concern.
Potentilla rimicola is known only from Tahquitz Peak in the San Jacinto Mountains, Riverside County, California, and the Sierra San Pedro Mártir in Baja California, Mexico. Plants are rooted in rock crevices, often on vertical surfaces, in contrast to P. wheeleri, which is rooted in the ground.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
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MD Biodiversity, 
MN Wildflowers, 
MO Plants, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
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