Potentilla plattensis
Potentilla flabellifolia
Platte cinquefoil, Platte River cinquefoil
fan-foil, fan-leaf cinquefoil, fanleaf or fanfoil or Mount Rainier cinquefoil, fringe-leaf cinquefoil, high mountain cinquefoil
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–)1–3 dm, lengths 2 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, ternate, (1–)3–12(–20) cm;
stipules: apex rounded;
petiole (0.5–)1–15(–18) cm, hairs and glands usually absent;
leaflets 3, central widely obovate to flabellate, (0.5–)1–5 × (0.4–)1–3(–3.5) cm, petiolule 0–5(–10) mm, margins flat, not or shallowly lobed (sinuses extending less than 1/2 to midvein), distal 1/2–3/4 usually unevenly incised 1/4–1/2 to midvein, teeth 3–7 per side, often secondarily toothed, surfaces similar, green, hairs absent or sparse, rarely common, 0.5–1 mm, glands absent or sparse.
1–3.
(1–)3–15(–20)-flowered, loosely cymose, sometimes racemiform.
1–6-flowered.
1–4(–5) cm, ± recurved in fruit.
straight, 0.3–4.5(–5) 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 often toothed or 2-lobed, elliptic to oval, 3.5–7 × (1–)1.5–3 mm, margins flat;
hypanthium 3–7 mm diam.;
sepals 4–8 mm, apex acute to obtuse;
petals dark yellow, (5–)6–10(–12) × (3–)5–10 mm;
filaments 1.5–3 mm, anthers 0.6–1.5 mm;
carpels 20–50, styles filiform, not or slightly papillate-swollen proximally, 1.6–2.5 mm.
(1.3–)1.5–1.9 mm, smooth, often ± carunculate.
1.2–1.5 mm.
= 70.
= 28.
Potentilla plattensis
Potentilla flabellifolia
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 flabellifolia is found in the mountains from southern British Columbia, southwestern Alberta, and southwestern Montana to the southern Sierra Nevada of California.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
SW CO Wildflowers- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
