Potentilla bipinnatifida |
Potentilla holmgrenii |
|
---|---|---|
bipinnate cinquefoil, potentille bipinnatifide, tansy cinquefoil |
Holmgren's cinquefoil |
|
Habit | Plants densely tufted to cushion-forming. | |
Caudex branches | stout, columnar, at least partly sheathed with marcescent whole leaves. |
|
Stems | ascending to erect, (1–)2–5 dm. |
ascending, 0.2–0.8 dm, lengths 1.5–2.5 times basal leaves. |
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. |
1.5–4 cm; petiole 0.5–2 cm, long hairs absent or sparse to common (less so than cottony hairs), ± appressed, 1–2 mm, soft, smooth, cottony hairs dense, other hairs and glands absent, sparse, or obscured; leaflets touching to overlapping, central broadly elliptic to obovate, 0.7–1.1 × 0.5–0.6 cm, sessile or short-petiolulate, petiolule to 1 mm, base cuneate, margins revolute, distal 1/2–3/4 incised ± 1/2 to midvein, teeth 2–4 per side, approximate, surfaces ± dissimilar, abaxial white to grayish white, long hairs 1 mm, cottony-crisped hairs dense, adaxial grayish green to grayish white, long and short-crisped hairs abundant to dense. |
Cauline leaves | 2–4. |
0–1. |
Inflorescences | (4–)10–50(–100)-flowered, congested or elongating in fruit. |
1–2(–3)-flowered. |
Pedicels | 0.2–0.8 cm (proximal to 2 cm). |
0.4–0.7 cm in flower, to 2 cm in fruit. |
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 to narrowly elliptic, 2–2.2 × 0.6–0.9 mm, 1/4–1/2 as wide as sepals, margins flat, red glands absent; hypanthium 1.8–2.2 mm diam.; sepals 3–3.5 mm, apex subacute; petals 4–5 × 2.5–4 mm, longer than sepals; filaments 1–1.5 mm, anthers 0.5 mm; carpels 30–40, apical hairs absent, styles narrowly columnar, not or ± papillate-swollen in proximal 1/5 or less, 1.2–1.4 mm. |
Achenes | 1–1.2 mm, smooth to faintly rugose. |
1.1–1.4 mm. |
2n | = 56. |
|
Potentilla bipinnatifida |
Potentilla holmgrenii |
|
Phenology | Flowering summer. | Flowering summer. |
Habitat | Open shortgrass prairie, alkaline bottoms, streamsides in sagebrush, disturbed sites | Wind-swept ridges, fellfields, rocky slopes |
Elevation | 10–3400 m (0–11200 ft) | 3300–4500 m (10800–14800 ft) |
Distribution |
AK; CO; ID; MI; MN; MT; ND; NE; NM; SD; UT; WY; AB; MB; NT; ON; QC; SK; YT
|
NV; UT |
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 holmgrenii is known only from the Schell Creek and Snake ranges, Nevada, and Deep Creek Range, Utah. In addition to characteristics given in the key, lateral leaflets and leaflet teeth of P. holmgrenii are directed more forward than in P. nivea, leaflets are thicker and more densely hairy, and the terminal tooth is often orbiculate and frequently overlapped by the adjacent pair of lateral teeth. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 217. | FNA vol. 9, p. 199. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Pensylvanicae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Niveae |
Sibling taxa | ||
Synonyms | P. pensylvanica var. bipinnatifida | |
Name authority | Douglas: in W. J. Hooker, Fl. Bor.-Amer. 1: 188. (1832) | D. F. Murray & Elven: J. Bot. Res. Inst. Texas 1: 811, figs. 1, 2. (2007) |
Web links |