Potentilla plattensis
Potentilla cristae
Platte cinquefoil, Platte River cinquefoil
crested cinquefoil, crested potentilla
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, 0.3–2 dm, lengths 2–3 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.
not in ranks, ternate, 1–5(–9) cm;
stipules: apex acute to obtuse;
petiole 1–4 cm, long hairs absent or sparse to common, spreading to ascending, 0.5–2 mm, ± weak, glands sparse to abundant;
leaflets 3, central flabellate, 0.4–2 × 0.5–1.5 cm, petiolule 1–3 mm, margins flat, distal 3/4+ deeply 3–5-lobed (sinuses extending 1/2 to nearly to midvein), lobes unevenly incised 1/4–1/2 to midvein, teeth 2–5 per lobe, surfaces similar, dark green, hairs ± sparse, 0.5–1.5 mm, glands sparse to abundant.
1–3.
(1–)3–15(–20)-flowered, loosely cymose, sometimes racemiform.
1–7-flowered.
1–4(–5) cm, ± recurved in fruit.
straight, 0.2–1.2(–2) cm, not much longer in fruit than in flower.
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 broadly ovate, 2–4 × 2 mm, margins flat;
hypanthium 3.5–6 mm diam.;
sepals 3–5 mm, apex broadly acute to obtuse;
petals yellow, 3–5.5 × 4–5 mm;
filaments 0.7–1.7 mm, anthers 0.5–0.6 mm;
carpels 25–40, styles tapered-filiform, ± papillate-swollen in proximal 1/5–/1/3, 1.3–2 mm.
(1.3–)1.5–1.9 mm, smooth, often ± carunculate.
1–1.5 mm, dorsally crested.
= 70.
= 42.
Potentilla plattensis
Potentilla cristae
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.)
Of conservation concern.
Potentilla cristae is known only from Cory Peak, Mount Eddy, and the Marble Mountains in northwestern California. In addition to the characteristics in the key, the species is distinctive in having a low dorsal crest on the achenes, hence the specific epithet.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
OR
Flora NW
PNW Herbaria
SW CO Wildflowers
WildflowerSearch
iNaturalist
USDA Plants Database
CA
