Potentilla breweri
Potentilla simplex
Brewer's cinquefoil
common cinquefoil, old-field cinquefoil, old-field five-fingers, potentille simple, simple cinquefoil
prostrate to ascending, (0.5–)1–3(–4.5) dm, lengths 2–4(–5) times basal leaves.
initially erect to ascending to 5 dm, then arching above ground-level, becoming prostrate, flagelliform, not branched, rooting at distal nodes, (0.5–)1.5–12 dm.
pinnate with distal leaflets ± confluent, (2–)4–12(–17) × 1–2.5(–5) cm;
petiole 1–3(–7) cm, straight hairs mostly absent, cottony hairs sparse to dense, glands absent or obscured to common;
primary lateral leaflets 3–6 per side, on distal 1/2–2/3(–3/4) of leaf axis, ± overlapping, largest ones cuneate-flabellate, 0.5–1.5(–2.5) × 0.4–2(–3) cm, distal 1/2 to whole margin unevenly incised 1/2 to completely to midvein (blade often medially split as well), ultimate teeth or segments 3–10, narrowly elliptic, 2–10(–15) × 1–3(–5) mm, apical tufts less than 1 mm, surfaces grayish green to white, not glaucous, straight hairs sparse to common (sparser adaxially), loosely appressed to ascending, 1–1.5 mm, soft, cottony hairs sparse to dense, glands sparse or obscured to common.
persistent or ephemeral, usually palmate, 3.5–20 cm;
petiole 1–15 cm, long hairs ± abundant, appressed to spreading, (0.5–)1–3 mm, weak to ± stiff, glands absent or sparse, sometimes common;
leaflets 5(–7), central narrowly elliptic to obovate, 1.5–5 × 0.5–2.5 cm, distal 1/2–3/4 of margin incised 1/4–1/3 to midvein, teeth 4–8(–13) per side, surfaces similar to ± dissimilar, abaxial green to silvery white, sparsely to abundantly hairy, adaxial green, glabrate or sparsely to moderately hairy.
1–3.
(0–)1 proximal to 1st flowering node, well expanded at anthesis, usually palmate, 2.5–6(–9) cm;
petiole 0–2(–4) cm;
leaflets (3–)5, often more elongate than those of basal leaves, ± elliptic to oblanceolate, sometimes obovate, 1.5–6(–7.5) × 0.5–2(–3) cm, apex acute to obtuse.
2–15(–25)-flowered, openly cymose.
solitary flowers at stolon nodes.
(1–)1.5–2.5(–4) cm, straight in fruit.
1–5(–8.5) cm.
epicalyx bractlets lanceolate to ovate, 2–5 × 1–1.5 mm;
hypanthium (3–)4–5 mm diam.;
sepals (3–)4–7 mm, apex acute;
petals 5–9(–10) × 4–8(–10) mm;
filaments (1–)2–4 mm, anthers (0.5–)1 mm;
carpels 15–25, styles 2–3 mm.
5(–6)-merous;
epicalyx bractlets linear to narrowly lanceolate, 2–5 × 1–1.5(–2) mm, often larger than sepals (especially in bud);
hypanthium 3–5 mm diam.;
sepals 4–6 mm, apex broadly acute;
petals 4–7 × 3–6 mm, apex rounded to ± retuse;
stamens ca. 20, filaments 0.5–2 mm, anthers 0.6–1 mm;
carpels 20–50, styles 0.8–1.5 mm.
1.8 mm, smooth, not carunculate.
0.9–1.2 mm, faintly rugose.
horizontal, irregularly thickened or moniliform, 1–8 cm.
= 72–73, 99, 100, 102.
Potentilla breweri
Potentilla simplex
Of conservation concern.
Potentilla breweri differs from other members of sect. Multijugae in its often dense, cottony vestiture. Density of cottony hairs and leaflet dissection can differ significantly between first-formed and mid- to late-season leaves of P. breweri; in the description above, leaves are those predominant at anthesis.
Potentilla breweri is most common in the Sierra Nevada of California, with sporadic occurrences to the Cascade Range in southern Washington. Disjunct populations occur in the Ruby and Snake ranges in Nevada and on Steens Mountain in Oregon, where often introgressed with P. versicolor. Reports from Utah are based on collections of P. concinna var. proxima or possible hybrids between P. concinna var. proxima and P. ovina var. decurrens.
J. Clausen et al. (1940) concluded that Potentilla breweri (with P. versicolor as synonym) belonged with P. bruceae and P. drummondii as members of a cenospecies that probably also included unnamed species (possibly P. ovina var. decurrens) from the mountains of Colorado, Utah, and Wyoming. Chromosome number varied within populations, and high numbers of univalents were present.
Recognition of Potentilla breweri as a distinct species differs from recent treatments in which it was considered to be a variety or subspecies of P. drummondii, parallel to the treatment of P. bruceae. The present continental perspective of the genus, as well as additional fieldwork, has resulted in the return of all three to species rank (B. Ertter and D. Mansfield 2007). Placement of P. breweri in sect. Multijugae, separate from P. bruceae and P. drummondii in sect. Graciles, is based on the commonly prostrate habit, fully pinnate leaves, and deeply divided overlapping leaflets.
Although B. C. Johnston (1980) used Potentilla breweri var. viridis Jepson to accommodate greener-than-average sparsely cottony plants, including populations treated here as P. versicolor, the type is probably a sterile hybrid with P. wheeleri as one parent (B. Ertter 1992). The type of P. millefolia var. algida Jepson (included by Johnston in the synonymy of var. viridis) and comparable plants from north-central California combine features of P. breweri and P. versicolor but are more glandular than either. This variant, as well as exceptionally small plants from the Warner Mountains of California, may prove distinct.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
The distinction between Potentilla simplex and P. canadensis is subtle, and the former is often misidentified as the latter; additional features to distinguish the two species are provided by M. L. Fernald (1931).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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