Potentilla argentea
Potentilla brunnescens
hoary cinquefoil, potentille argentée, silver cinquefoil, silver-leaf cinquefoil, silvery cinquefoil
brownish cinquefoil, slender brown cinquefoil, slender cinquefoil
conspicuous, usually golden.
mostly decumbent to ascending, 1–6 dm.
ascending to nearly erect, (1.5–)3–7 dm.
palmate.
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.
2–9, proximal ones 2–7(–10) cm;
proximal petioles 1–4(–7) cm, long hairs absent or sparse, ± ascending, 1–2 mm, soft, short and crisped hairs absent or obscured, cottony hairs dense, glands absent or obscured;
leaflets 5(–7), central one ± oblanceolate, (0.5–)1–3 × 0.3–1(–1.3) cm, margins revolute, distal 1/2–2/3 evenly or unevenly incised 1/2–3/4+ to midvein, teeth 2–3 per side (more if lobed or secondarily toothed), surfaces strongly dissimilar, abaxial white, long hairs ± sparse (mostly on veins), 1–2 mm, weak, short and crisped hairs absent or obscured, cottony hairs dense, glands absent or obscured, adaxial long hairs absent or sparse to common, short or crisped hairs absent or sparse, cottony hairs absent, glands absent or sparse.
1–3(–4).
10–80-flowered.
12–30(–70)-flowered.
0.3–1.5(–2) cm.
0.2–1(–4) cm.
epicalyx bractlets oblong to narrowly ovate, 1.5–3 × 0.7–1.2 mm, lengths 2/3–1 times sepals;
sepals 2–4.5 mm, apex ± acute;
petals (2–)2.5–4 × 1.5–3 mm;
filaments 0.8–1.5 mm, anthers 0.3–0.6(–0.8) mm;
carpels 30–60, styles 0.6–0.9 mm, often strongly papillate-swollen proximally.
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.
0.8–1.1 mm, smooth to lightly rugose.
1.5 mm.
= 14, 28, 35, 42, 56, 62 (Eurasia).
Potentilla argentea
Potentilla brunnescens
The bright, silvery vestiture of the leaves quickly distinguishes Potentilla argentea from P. inclinata and P. intermedia. Although treated here as introduced, some (P. A. Rydberg 1898; P. A. Werner and J. D. Soule 1976) considered P. argentea to be probably native in eastern North America.
The Potentilla argentea species group is an amphi- or apomictic polyploid complex that has been the subject of numerous cytological, sexual, and molecular studies (for example, A. Müntzing and G. Müntzing 1945; A. Müntzing 1958; J. Paule et al. 2011). Taxonomic treatments have ranged from a highly polymorphic single species to an abundance of species, varieties, and forms (T. Wolf 1908). This treatment is at the conservative end of the spectrum. Some New England references (R. C. Bean et al. 1967; F. C. Seymour 1969) distinguish plants with densely white-hairy adaxial leaflet surfaces as var. pseudocalabra Th. Wolf, a name based on plants from southeastern Europe. Molecular analysis by Paule et al. supports the conclusion by Wolf that the variety consists of intermediates between P. argentea and P. calabra Tenore. The optimum taxonomic disposition of var. pseudocalabra, and whether any North American plants are properly included, remains to be determined.
Potentilla argentea has been reported as an active agent in treating cirrhosis of the liver (N. T. Starostenko and V. N. Starostenko 1971).
(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.)
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