Potentilla bipinnatifida
Potentilla macounii
bipinnate cinquefoil, potentille bipinnatifide, tansy cinquefoil
Macoun's cinquefoil
ascending to erect, (1–)2–5 dm.
0.4–1.5(–2) dm, lengths 2 times basal leaves.
subpinnate to subpalmate, (6–)10–25 cm;
petiole (2–)5–15 cm, long hairs dense, appressed, 1–2 mm, soft to ± stiff, short hairs absent, crisped hairs sparse, glands absent, sparse, or obscured;
leaflets 2–3 per side, on distal 1/6–1/3(–1/2) of leaf axis, separate to ± overlapping, terminal ones oblanceolate, (2–)3–6(–10) × 1–2(–3.5) cm, margins revolute, incised 3/4+ to midvein, undivided medial blade 1.5–6 mm wide, teeth 5–8 per side, ± linear, surfaces ± to strongly dissimilar, abaxial usually white, rarely grayish, long hairs abundant especially on veins, 1–2 mm, ± weak, short hairs absent or obscured, cottony (and crisped) hairs ± dense, glands absent or obscured, adaxial green to grayish, long hairs sparse to abundant, loosely appressed, 0.5–1.5 mm, short hairs absent or sparse, crisped and/or cottony hairs sparse to common, glands sparse to common.
subpinnate to pinnate, usually at least 2 pairs of leaflets separate from terminal leaflets, distal leaflets often confluent, 2–7 cm;
petiole 1–4(–8) cm, straight hairs abundant, ± appressed to ascending, 1–2 mm, stiff to weak, cottony hairs sometimes present, glands absent or obscured;
leaflets 5–9(–11), on distal 1/5–1/2 of leaf axis, strongly overlapping, proximal pair separate from others by 1–5 mm of leaf axis, central leaflets oblanceolate to obovate, sometimes lobed, (0.5–)1–1.5 × 0.5–1 cm, petiolules 0–1 mm, distal 2/3 of margins incised 1/2+ to midvein, teeth 2–5 per side, touching, 1–3 mm, surfaces ± dissimilar, abaxial white, straight hairs ± abundant, ± appressed, 1–1.5 mm, weak to stiff, cottony hairs ± dense, glands absent or obscured, adaxial greenish gray, straight hairs sparse to abundant, usually appressed, sometimes ascending, 1 mm, usually ± stiff, sometimes soft, cottony hairs sparse, glands obscured.
2–4.
(4–)10–50(–100)-flowered, congested or elongating in fruit.
(1–)3–6(–10)-flowered.
0.2–0.8 cm (proximal to 2 cm).
0.8–2 cm.
epicalyx bractlets narrowly elliptic to lanceolate, 2.5–6 mm, lengths ± 2/3 times sepals, margins flat;
hypanthium 3–5 mm diam.;
sepals 3–6 mm, apex ± acute, abaxial surfaces: venation indistinct, glands absent, sparse, or obscured;
petals yellow, 3–5 × 3–4 mm, lengths ± equal to sepals;
filaments 0.5–2 mm, anthers 0.3–0.5 mm;
carpels 50–80, styles papillate-swollen in proximal 1/2–3/4+, 1–1.2 mm.
epicalyx bractlets lanceolate to ovate-elliptic, 2.5–4 × 0.8–1.5 mm;
hypanthium 3–4 mm diam.;
sepals (3–)3.5–5.5(–6) mm, apex ± acute;
petals 6–7 × 5–7 mm;
filaments 1.5–3 mm, anthers 0.8–1 mm;
carpels 15–20, styles 2–2.5 mm.
1–1.2 mm, smooth to faintly rugose.
1.5–2 mm, smooth.
= 56.
Potentilla bipinnatifida
Potentilla macounii
Potentilla bipinnatifida is similar to P. litoralis in habit and leaf dissection but has flat, silky epicalyx bractlets and sepals with no evident glands. Vestiture is generally silkier, and the silvery to bicolor leaves are white-cottony abaxially. The two species are sympatric in the plains of Canada, with some intergradation; P. bipinnatifida is also common south to Colorado, where it is found in intermontane meadows and sagebrush flats. Outlying populations occur in Blaine and Custer counties, Idaho, and Duchesne and Piute counties, Utah. Eastern collections from disturbed sites might be adventive.
Potentilla missourica Hornemann ex Lindley and P. normalis Besser ex Sprengel are older names for this species; both were rejected against a conserved P. bipinnatifida with designated lectotypes (see J. Soják 2008b).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Of conservation concern.
Potentilla macounii differs from other species in sect. Concinnae in the combination of subpinnate leaves, with at least two proximal pairs of leaflets separated from the terminal leaflets, and in having somewhat softer hairs. It occurs on the eastern slopes of the Rocky Mountains in southwestern Alberta (where of conservation concern) and in western Montana. Some problematic collections from the Absaroka Range in western Wyoming are most comparable to P. macounii, but have softer vestiture and somewhat larger, less divided, more subpalmate leaves. If these Wyoming populations were included in P. macounii, the upper elevation range would be 3300 m.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
BC
MI Flora
MN Wildflowers
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WildflowerSearch
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