Potentilla bipinnatifida
Potentilla saximontana
bipinnate cinquefoil, potentille bipinnatifide, tansy cinquefoil
Rocky Mountains cinquefoil
ascending to erect, (1–)2–5 dm.
(0.2–)0.4–1(–1.5) dm.
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.
subpalmate to pinnate, (1–)1.5–4(–7) cm;
petiole 0.5–2(–4) cm, vestiture not or scarcely seasonally dimorphic, long hairs abundant to dense, appressed to spreading, 1–1.5(–2) mm, weak to ± stiff, cottony hairs usually absent, crisped hairs absent or sparse, glands sparse;
leaflets 3 at tip of leaf axis plus 1–2(–3) additional pairs separated from tip by 1–5 mm, on distal 1/10–1/3 of leaf axis, largest leaflets obovate to oblanceolate, 0.5–1.5 × 0.3–1.2 cm, ± whole margin incised 1/2–3/4 to midvein, teeth 2–4(–5) per side, separate to overlapping, 1–4 mm, surfaces ± dissimilar, abaxial grayish green to white, straight hairs abundant, 1–1.5 mm, cottony and crisped hairs sparse to dense, rarely absent, glands sparse or obscured, adaxial green to grayish, straight hairs sparse to abundant, 1–2 mm, cottony hairs absent or rarely sparse, crisped hairs absent or sparse, glands ± sparse.
2–4.
0–1(–2).
(4–)10–50(–100)-flowered, congested or elongating in fruit.
(1–)2–5(–10)-flowered.
0.2–0.8 cm (proximal to 2 cm).
0.5–1.5 cm (proximal to 2.5 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 ± ovate-elliptic, 2–4 × 1–1.5 mm;
sepals 3.5–5 mm, apex bluntly acute;
petals 4–6(–8) × 4–7 mm;
filaments 0.5–2 mm, anthers 0.5 mm;
carpels 10–20+, styles columnar-filiform, papillate-swollen at base, if at all, 0.8–1.5 mm.
1–1.2 mm, smooth to faintly rugose.
1.5 mm.
= 56.
Potentilla bipinnatifida
Potentilla saximontana
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.)
Potentilla saximontana is a small plant of very high elevations in the mountains of Colorado, the La Sal and Uinta mountains of Utah, and the Absaroka and Beartooth mountains of Wyoming and Montana. Although sometimes confused with P. rubricaulis (for example, W. A. Weber and R. C. Wittman 1996), the subpinnate leaves, open few-flowered inflorescences, and columnar-filiform styles make P. saximontana a distinct species.
The lectotype of Potentilla nivea Linnaeus var. dissecta S. Watson [= P. saximontana var. dissecta (S. Watson) Soják] has been tentatively included in P. saximontana (B. Ertter 2008), but P. saximontana is not otherwise known from the Canadian Rockies. See B. Ertter et al. (2013) for additional discussion.
The combination Potentilla rubripes Rydberg var. saximontana (Rydberg) Th. Wolf is incorrect, in that P. saximontana is the older name.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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