Potentilla plattensis
Potentilla multisecta
Platte cinquefoil, Platte River cinquefoil
featherleaf cinquefoil, Great Basin 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.
0.5–2(–2.7) dm, lengths 1–2(–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.
usually palmate, sometimes subpalmate, 3–12(–15) cm;
petiole 1–6(–13) cm, straight hairs ± abundant, ± appressed, 1–1.5 mm, stiff, cottony hairs absent, glands absent or sparse;
leaflets (3–)5, usually on tip, sometimes to distal 1/4 of leaf axis, ± overlapping, proximal pair separated from others by 0–10 mm of leaf axis, central leaflets ± obovate, 1–2.5(–4) × (0.5–)1–1.5(–2) cm, petiolule 0–2 mm, distal 1/2+ of margins incised 3/4+ to midvein, teeth 2–5 per side, separate, 3–10(–14) mm, surfaces similar, green to grayish, straight hairs sparse to abundant, appressed, 1–1.5 mm, usually stiff, short crisped hairs sometimes present, cottony hairs absent, glands absent or sparse.
1–3.
(1–)3–15(–20)-flowered, loosely cymose, sometimes racemiform.
(1–)2–6(–10)-flowered.
1–4(–5) cm, ± recurved in fruit.
1–3(–4) 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-elliptic to narrowly ovate, 2–4 × 1–1.5 mm;
hypanthium 3–5 mm diam.;
sepals 3–5(–6) mm, apex ± acute;
petals (2.5–)5–7 × (2–)4–5 mm;
filaments 1–2 mm, anthers 0.6–1 mm;
carpels 5–20, styles 2–3 mm.
(1.3–)1.5–1.9 mm, smooth, often ± carunculate.
2–2.5 mm, smooth.
= 70.
Potentilla plattensis
Potentilla multisecta
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 center of distribution of Potentilla multisecta is northeastern Nevada and northwestern Utah; the best disposition of more northern populations, which tend to be hairier and more compact, is unresolved. Populations in eastern Idaho, southwestern Montana, and western Wyoming are components of an unresolved zone of apparent intergradation that also includes P. ovina var. ovina (sect. Multijugae), P. glaucophylla var. perdissecta (sect. Graciles), and members of sect. Subjugae. Significant variation also exists among populations in Nevada and Utah. Not included here are some subpalmate collections from Saskatchewan that would key to P. multisecta (for example, A. Breitung 4045, MO, RM), whose optimum disposition has yet to be resolved.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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Flora NW
PNW Herbaria
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WildflowerSearch
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USDA Plants Database
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