Potentilla plattensis
Potentilla stipularis
Platte cinquefoil, Platte River cinquefoil
stipulate cinquefoil, stipulated cinquefoil
mostly absent.
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.
(0.2–)1–2.5(–3.5) dm.
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.
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.
1–3.
1–3;
stipules fused with all or most of petiole, free portion shorter than fused portion.
(1–)3–15(–20)-flowered, loosely cymose, sometimes racemiform.
2–5-flowered.
1–4(–5) cm, ± recurved in fruit.
1–3 cm (proximalmost to 6 cm).
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 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.
(1.3–)1.5–1.9 mm, smooth, often ± carunculate.
1.1–1.3 mm, smooth.
= 70.
= 28 (Eurasia).
Potentilla plattensis
Potentilla stipularis
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.)
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.)
OR
Flora NW
PNW Herbaria
SW CO Wildflowers
WildflowerSearch
iNaturalist
USDA Plants Database
