Potentilla bipinnatifida
Potentilla hickmanii
bipinnate cinquefoil, potentille bipinnatifide, tansy cinquefoil
Hickman's cinquefoil
ascending to erect, (1–)2–5 dm.
usually prostrate to decumbent, sometimes ± ascending in supporting vegetation, 0.5–2.5 dm, lengths 1–2 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.
pinnate with distal leaflets ± confluent, 3–17 × 1–3.5 cm;
petiole 1–5 cm, straight hairs sparse to common, appressed, 0.5–1.5(–2) mm, stiff, cottony hairs absent, glands absent or sparse;
primary lateral leaflets 3–6 per side, on distal 1/2–2/3 of leaf axis, ± overlapping to nearly separate, largest ones cuneate to flabellate, 0.5–2 × 0.5–1.5 cm, distal 1/2 to whole margin ± palmately incised 1/2–2/3(+) to midvein, ultimate teeth or segments 2–5, narrowly elliptic to oblanceolate, 2–10(–15) × (1–)1.5–3 mm, apical tufts 0.5 mm, surfaces green, not glaucous, straight hairs sparse to common (often sparser to glabrate adaxially), appressed, 1–1.5 mm, stiff, cottony hairs absent, glands absent or inconspicuous.
2–4.
2.
(4–)10–50(–100)-flowered, congested or elongating in fruit.
2–5-flowered, very openly cymose, sometimes racemiform.
0.2–0.8 cm (proximal to 2 cm).
1–2(–4) cm, ± recurved in fruit.
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 ± elliptic, 3.5–6 × (1–)1.5–2.5 mm;
hypanthium 3–5 mm diam.;
sepals 3.5–7(–9) mm, apex acute;
petals 6–12 × 5–9 mm;
filaments (1.5–)2–3(–4) mm, anthers 0.7–1.2 mm;
carpels (2–)5–15, styles 2.5–3.5 mm.
1–1.2 mm, smooth to faintly rugose.
2 mm, smooth, ± carunculate.
= 56.
Potentilla bipinnatifida
Potentilla hickmanii
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 hickmanii is known from only two extant populations in Monterey and San Mateo counties. The species is a federally listed endangered species (U.S. Fish and Wildlife Service, ecos.fws.gov/docs/recovery_plan/050617a.pdf). Plants from Sonoma County formerly included in P. hickmanii now constitute P. uliginosa. Although some morphologic overlap occurs with P. millefolia, P. hickmanii generally differs in having less dissected leaflets occupying less of the leaf axis, as well as somewhat larger flowers bearing fewer carpels.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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