Potentilla biennis
Potentilla saximontana
biennial cinquefoil, biennial or Greene's cinquefoil, Greene's cinquefoil
Rocky Mountains cinquefoil
ascending to erect, (1–)2–6(–8.5) dm, hairs at base not stiff, not tubercle-based, glands sparse to abundant, conspicuous (to 1 mm, septate).
(0.2–)0.4–1(–1.5) dm.
ternate, (2–)4–12(–25) cm;
petiole (1–)2–8(–20) cm, long hairs sparse to common, spreading to ascending, 0.5–1.5(–3) mm, weak, crisped hairs usually absent, glands sparse to abundant, conspicuous (to 1 mm, septate);
leaflets 3, at tip of leaf axis, usually overlapping, largest ones mostly obovate or oval to nearly round, (0.5–)1–3(–4) × 0.3–3(–3.5) cm, distal 3/4 to ± whole margin evenly to unevenly incised 1/4–1/3(–1/2) to midvein, teeth 3–8(–13) per side, surfaces sparsely to moderately hairy, rarely glabrate, glands sparse to abundant at least abaxially.
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.
0–1(–2).
(10–)20–70+-flowered.
(1–)2–5(–10)-flowered.
0.2–1(–2) cm.
0.5–1.5 cm (proximal to 2.5 cm).
epicalyx bractlets narrowly oblanceolate to narrowly obovate or elliptic, (1.5–)2–3.5(–4.5) × 0.5–1.5(–2) mm;
hypanthium (2–)3–4(–5.5) mm diam.;
sepals (2–)3–5 mm, apex broadly acute to obtuse;
petals pale yellow to yellow, broadly oblanceolate to obovate, (1–)2–2.7 × 1.5 mm;
stamens 10 or 15, filaments 0.5–1.2 mm, anthers 0.2–0.3 mm;
carpels 40–100, styles 0.5–0.7 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.
whitish or pale yellowish, 0.5–0.9 mm, smooth, without a corky protuberance.
1.5 mm.
Potentilla biennis
Potentilla saximontana
Potentilla biennis may be recognized by its septate hairs with a round, terminal gland, which dominate the vestiture especially at the base of the plant. Stems are more commonly erect and leaflets rounder than those of P. rivalis. The species is most common along the eastern side of the Sierra Nevada of California, across the Intermountain Region to the Rocky Mountains. All specimens seen by the authors from Baja California, Mexico, which were previously referred to P. biennis are now assigned to P. rivalis.
J. Soják (1996) lectotypified Potentilla millegrana Engelmann ex Lehmann upon a collection of P. rivalis, thus preventing P. biennis from being a later taxonomic synonym.
(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.)
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
