Potentilla bipinnatifida |
Potentilla albiflora |
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bipinnate cinquefoil, potentille bipinnatifide, tansy cinquefoil |
Pinaleño cinquefoil, whiteflower cinquefoil |
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Stems | ascending to erect, (1–)2–5 dm. |
0.2–1.5 dm. |
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. |
ternate, 1.5–10 cm; petiole 1–7 cm, long hairs ± abundant, spreading to ascending, 0.5–1(–1.5) mm, weak to stiff, glands sparse to abundant; leaflets 3, central obovate, 0.5–2.5(–3.5) × 0.4–1.3(–2) cm, not to scarcely petiolulate, distal 1/2–2/3 of margins evenly incised ± 1/3 to midvein, teeth 3–5(–6) per side, surfaces green, long hairs ± abundant, 0.5–1 mm, glands sparse to abundant. |
Cauline leaves | 2–4. |
|
Inflorescences | (4–)10–50(–100)-flowered, congested or elongating in fruit. |
1–5(–10)-flowered. |
Pedicels | 0.2–0.8 cm (proximal to 2 cm). |
0.5–2 cm. |
Flowers | 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-elliptic, (1.5–)2–3(–5) × 0.5–1.5 mm; hypanthium 3.5–6 mm diam.; sepals 3–6(–8) mm, apex acute; petals ± paler abaxially, bright yellow adaxially, narrowly obcordate, (3–)4–7(–8) × 3–5 mm; filaments 2–4 mm, anthers 0.5–1 mm; carpels 10–25, styles 2–3 mm. |
Achenes | 1–1.2 mm, smooth to faintly rugose. |
1.5 mm, smooth. |
Short | hairs not well differentiated from long hairs, absent or sparse throughout. |
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2n | = 56. |
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Potentilla bipinnatifida |
Potentilla albiflora |
|
Phenology | Flowering summer. | Flowering May–Sep. |
Habitat | Open shortgrass prairie, alkaline bottoms, streamsides in sagebrush, disturbed sites | Rocky slopes, open ground, in pine-oak and mixed conifer woodlands |
Elevation | 10–3400 m (0–11200 ft) | 1800–3200 m (5900–10500 ft) |
Distribution |
AK; CO; ID; MI; MN; MT; ND; NE; NM; SD; UT; WY; AB; MB; NT; ON; QC; SK; YT
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AZ |
Discussion | 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 albiflora grows on the Pinaleño (Graham) Mountains in Graham County, with a few outlying collections known from the Mogollon Rim in Greenlee County and the Santa Catalina Mountains of Pima County. Contrary to the specific epithet, petals of living plants are yellow, not white; like those of many Potentilla species, they tend to fade in pressed material. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 217. | FNA vol. 9, p. 186. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Pensylvanicae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Subviscosae |
Sibling taxa | ||
Synonyms | P. pensylvanica var. bipinnatifida | |
Name authority | Douglas: in W. J. Hooker, Fl. Bor.-Amer. 1: 188. (1832) | L. O. Williams: Bull. Torrey Bot. Club 61: 260. (1934) |
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