Potentilla plattensis
Potentilla crantzii
Platte cinquefoil, Platte River cinquefoil
alpine cinquefoil, potentille de crantz
initially decumbent to sometimes ascending, becoming prostrate or supported by vegetation, (0.3–)0.5–3.5(–4.5) dm, lengths 1.5–2.5(–4) times basal leaves.
ascending to erect, 0.5–2(–3) dm, lengths 1.5–3 times basal leaves.
pinnate with distal leaflets ± distinct, 2–15(–20) × 1–3 cm;
petiole 0.5–5 cm, straight hairs common, tightly appressed, 0.5(–1) mm, stiff, cottony hairs absent, glands absent or sparse;
primary lateral leaflets (3–)4–6(–8) per side, on distal (1/4–)1/2–3/4 of leaf axis, overlapping to separate, largest ones obovate, 0.5–1.5(–2) × 0.5–1(–1.3) cm, distal (1/2–)2/3 to whole margin pinnately incised 3/4+ to midvein, ultimate teeth 5–10, linear-oblanceolate, 1.5–8(–10) × 1–2 mm, apical tufts less than 0.5 mm, surfaces green to grayish green, not glaucous, straight hairs sparse to common (sparser adaxially), tightly appressed, 0.5 mm, stiff, cottony hairs absent, glands absent or inconspicuous.
2-ranked, usually palmate, sometimes ternate, 2–10(–15) cm;
stipules: apex obtuse to truncate, rarely acute;
petiole 0.5–6.5(–10) cm, long hairs usually ± sparse, usually ± ascending, sometimes spreading or appressed, 1–2.5 mm, weak to ± stiff, glands absent or sparse;
leaflets 3–5, central obovate, 1.5–3(–3.5) × 0.8–1.5(–2) cm, petiolule 0–1 mm, margins flat, not lobed, distal 1/2–2/3 evenly incised 1/3–1/2 to midvein, teeth 3–4(–5) per side, not secondarily toothed, surfaces similar, green, not glaucous, hairs absent or sparse, rarely common, 0.8–1.5 mm, glands absent or sparse to abundant (fewer adaxially).
1–3.
(1–)3–15(–20)-flowered, loosely cymose, sometimes racemiform.
(2–)3–8(–12)-flowered.
1–4(–5) cm, ± recurved in fruit.
straight, 1–3(–4) cm in flower, to 6 cm in fruit.
epicalyx bractlets narrowly elliptic to linear-lanceolate, 2–5(–6) × 0.5–2 mm;
hypanthium 3–4 mm diam.;
sepals 3–6 mm, apex acute;
petals 4–7 × 3–6 mm;
filaments 1–2.5 mm, anthers 0.5–1 mm, usually ± 1/2 as long as filaments;
carpels 10–20, styles 1.5–2.5 mm.
epicalyx bractlets ovate or narrowly ovate, (1.5–)2.5–4 × (0.8–)1–1.3 mm, margins flat;
hypanthium 3–4 mm diam.;
sepals (3–)4–5(–6) mm, apex broadly acute;
petals yellow, 4–7(–9) × 4–8 mm;
filaments 1.8–2.2 mm, anthers 0.3–0.6 mm;
carpels 30–40, styles columnar-filiform, not papillate-swollen proximally, 1–1.6 mm.
(1.3–)1.5–1.9 mm, smooth, often ± carunculate.
1.2 mm.
= 70.
= 42; 28, 35, 49 (Europe).
Potentilla plattensis
Potentilla crantzii
Potentilla plattensis occurs mostly east of the Continental Divide from the Canadian Prairies to the mountains of New Mexico. The species barely enters Idaho at Monida Pass (Clark County). Populations also exist in the White Mountains of east-central Arizona and the mountains of southern Utah. The species is relatively uniform throughout its range but there is often significant seasonal variation, such that plants can be compact and densely strigose in early summer but elongate and subglabrous later in the season.
Where the ranges of Potentilla plattensis and P. ovina overlap, the two are sometimes difficult to distinguish. The habitats are usually distinct, in that P. plattensis generally occurs in moist valley bottoms and P. ovina occurs in rocky uplands. Differences in vestiture are also diagnostic: hairs of P. plattensis are 0.5 mm and tightly appressed; those of P. ovina are longer and looser.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Potentilla crantzii is primarily European, not restricted to coasts as in North America. The nomenclatural history is long and complex (A. Kurtto et al. in J. Jalas et al. 1972+, vol. 13), with P. alpestris and P. maculata in greatest historical use. The name P. ×protea Soják is available for presumed hybrids between P. crantzii and P. hyparctica.
The emphasis on two-ranked leaves to distinguish Potentilla crantzii from P. verna follows J. Soják (pers. comm.). Some collections of P. crantzii from Newfoundland approach P. verna in their more elongate caudex branches and shorter stature.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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Flora NW
PNW Herbaria
SW CO Wildflowers
WildflowerSearch
iNaturalist
USDA Plants Database
