Potentilla argentea
Potentilla robbinsiana
hoary cinquefoil, potentille argentée, silver cinquefoil, silver-leaf cinquefoil, silvery cinquefoil
dwarf mountain cinquefoil, Robbins' cinquefoil, White Mountains cinquefoil
mostly decumbent to ascending, 1–6 dm.
spreading to erect, 0.1–0.4 dm, lengths 1–2 times basal leaves.
palmate.
not in ranks, ternate, 1–2 cm;
stipules: apex broadly acute;
petiole 0.7–3 cm, long hairs sparse to abundant, spreading to subappresed, 0.2–2 mm, weak, glands sparse to common;
leaflets 3, central obovate, 0.5–1.3 × 0.2–1 cm, petiolule 0–1 mm, margins flat to ± revolute, not lobed, distal ± 2/3 evenly incised ± 1/2 to midvein, teeth 2–4(–5) per side, surfaces similar, green, hairs ± abundant (or nearly absent adaxially), 0.5–1 mm, glands sparse to common.
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.
10–80-flowered.
1(–2)-flowered.
0.3–1.5(–2) cm.
straight, 0.5–3 cm, not much longer in fruit than in flower.
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 oblong to elliptic, (1.8–)2–2.5(–3) × 0.7–1.2(–1.4) mm, ± equal to sepals, margins flat to ± revolute;
hypanthium (4–)5–7 mm diam.;
sepals (1.8–)2–2.5(–3) mm, apex broadly acute;
petals yellow, 2–3 × 2–3 mm;
filaments 0.5–1 mm, anthers 0.4–0.6 mm;
carpels 20–30, styles columnar-tapered, sometimes ± papillate-swollen in proximal 1/3–1/2, 0.8–1 mm.
0.8–1.1 mm, smooth to lightly rugose.
1–1.3 mm.
= 14, 28, 35, 42, 56, 62 (Eurasia).
= 49.
Potentilla argentea
Potentilla robbinsiana
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.)
Of conservation concern.
Potentilla robbinsiana is known only from two sites in the White Mountains, Monroe County, New Hampshire, and is reported in Vermont. Additional populations have been established nearby as a result of transplant efforts. Listed in 1980 as a federally endangered species, an intense recovery program resulted in the species being delisted in 2002.
Some early specimens were distributed as Potentilla frigida Villars, a similar European species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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