Potentilla bipinnatifida |
Potentilla brunnescens |
|
---|---|---|
bipinnate cinquefoil, potentille bipinnatifide, tansy cinquefoil |
brownish cinquefoil, slender brown cinquefoil, slender cinquefoil |
|
Glands | conspicuous, usually golden. |
|
Stems | ascending to erect, (1–)2–5 dm. |
ascending to nearly erect, (1.5–)3–7 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. |
sometimes 2-ranked, palmate, (5–)10–30 cm; petiole (1.5–)5–25(–50) cm, long hairs sparse to abundant, appressed to spreading, 1–2 mm, ± stiff, short, crisped, and cottony hairs absent, glands ± abundant; leaflets (5–)7–9, at tip of leaf axis, separate to slightly overlapping, largest ones oblanceolate-elliptic to narrowly obovate, (2–)5–10 × 1–4 cm, margins flat to ± revolute, distal 3/4 to nearly whole length ± evenly incised (1/4–)1/2–3/4+ to midvein, undivided medial blade 2–15(–20) mm wide, teeth (5–)7–10 per side, linear to broadly lanceolate, 3–15 mm, surfaces ± similar, abaxial paler, green, not glaucous, long hairs sparse to common, short-crisped hairs absent or sparse, cottony hairs absent, glands ± abundant. |
Cauline leaves | 2–4. |
1–3(–4). |
Inflorescences | (4–)10–50(–100)-flowered, congested or elongating in fruit. |
12–30(–70)-flowered. |
Pedicels | 0.2–0.8 cm (proximal to 2 cm). |
0.2–1(–4) 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 to elliptic, 3–6 × 1–2 mm, hairs sparse to common, loosely appressed to spreading, glands common to abundant; hypanthium 4–6(–8) mm diam.; sepals 4–8(–9) mm, apex acute to acuminate; petals 6–9 × 6–10 mm; filaments 1–2 mm, anthers 0.6–1 mm; carpels 30–60, styles filiform-tapered, papillate-swollen proximally, 1.5–2 mm. |
Achenes | 1–1.2 mm, smooth to faintly rugose. |
1.5 mm. |
2n | = 56. |
|
Potentilla bipinnatifida |
Potentilla brunnescens |
|
Phenology | Flowering summer. | Flowering summer. |
Habitat | Open shortgrass prairie, alkaline bottoms, streamsides in sagebrush, disturbed sites | Vernally moist rocky flats, sagebrush benchlands and slopes, usually basaltic |
Elevation | 10–3400 m (0–11200 ft) | 400–3100 m (1300–10200 ft) |
Distribution |
AK; CO; ID; MI; MN; MT; ND; NE; NM; SD; UT; WY; AB; MB; NT; ON; QC; SK; YT
|
AK; CO; ID; MT; OR; UT; WA; WY |
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.) |
The conspicuous golden glands, dark green color, and relatively broad leaflets make Potentilla brunnescens one of the better-defined species of sect. Graciles, though it has often been treated as a variety of P. gracilis. The glands, which are often on septate stalks, are particularly conspicuous on the epicalyx bractlets, hypanthium, and sepals, and at the junction of petiole and leaflets. The species occurs from the Blue Mountains of Oregon and Washington to western Montana, northern Utah, and north-central Colorado; collections from Alaska are probably not native. As presented here, Potentilla brunnescens encompasses two morphological extremes that might merit varietal status. Leaflets of the more common and widespread extreme are incised about halfway to the midvein; in contrast, some populations in western Wyoming and adjacent Idaho have leaflets incised 3/4 or more to the midvein. The latter have often been assigned to P. gracilis var. elmeri while reserving P. gracilis var. brunnescens for the former; this is untenable because the type of P. brunnescens is the latter form. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 217. | FNA vol. 9, p. 157. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Pensylvanicae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Graciles |
Sibling taxa | ||
Synonyms | P. pensylvanica var. bipinnatifida | P. gracilis var. brunnescens |
Name authority | Douglas: in W. J. Hooker, Fl. Bor.-Amer. 1: 188. (1832) | Rydberg: Bull. Torrey Bot. Club 28: 173. (1901) |
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