Potentilla plattensis
Potentilla verna
Platte cinquefoil, Platte River cinquefoil
spring 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.
prostrate to decumbent, rarely weakly erect, 0.3–1.5 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.
not in ranks, palmate, 2–5(–10) cm;
stipules: apex acuminate to acute, rarely obtuse;
petiole 1–6 cm, long hairs common, ascending to appressed, 1–2.5 mm, weak to ± stiff, glands absent or sparse;
leaflets 5–7, central oblanceolate to obovate, (0.8–)1–3 × 0.4–1.5 cm, petiolule 0–2 mm, margins flat, not lobed, distal 1/4–1/2(–2/3) evenly incised ± 1/3 to midvein, teeth 2–4(–5) per side, surfaces similar, green, hairs absent especially adaxially or sparse, 0.5–1.5(–2) mm, glands absent or sparse.
1–3.
(1–)3–15(–20)-flowered, loosely cymose, sometimes racemiform.
3–5(–6)-flowered.
1–4(–5) cm, ± recurved in fruit.
often recurved, 1–3(–4) 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 lanceolate, 3.5–5 × 1–1.5 mm, margins flat;
hypanthium 2–4 mm diam.;
sepals 3–5 mm, apex broadly acute to obtuse;
petals yellow, 5–8(–10) × 4–6 mm;
filaments 0.8–2 mm, anthers 0.5–0.8 mm;
carpels 40–60, styles ± columnar, not papillate-swollen proximally, 1 mm.
(1.3–)1.5–1.9 mm, smooth, often ± carunculate.
1.5–2 mm.
= 70.
= 28, 35, 42, 49, 56, 63, 70, 84 (Europe).
Potentilla plattensis
Potentilla verna
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 use of the name Potentilla verna here reflects the successful proposal by J. Soják (2009) to conserve P. verna with a conserved type. Alternatives in recent use include P. neumanniana Reichenbach (misapplied) and P. tabernaemontani. The species has an established horticultural presence, primarily as a ground cover, and is to be expected in North America beyond where reported here.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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