Potentilla argentea
Potentilla rubricaulis
hoary cinquefoil, potentille argentée, silver cinquefoil, silver-leaf cinquefoil, silvery cinquefoil
red-stem cinquefoil, Rocky Mountain cinquefoil
not sheathed with marcescent whole leaves.
mostly decumbent to ascending, 1–6 dm.
ascending to nearly erect, 1.5–4 dm.
palmate.
often both ternate and palmate on same plant, rarely subpalmate, 4–10 cm;
petiole 2.5–7 cm, long hairs sparse to common, loosely appressed to ascending-spreading, 1–2 mm, ± weak to stiff, verrucose, short and/or ± crisped hairs common to abundant, cottony hairs absent, glands usually sparse;
leaflets 3–5, proximalmost separated by 0(–1) mm, central oblong to obovate, 1.5–4 × 1–2.5 cm, petiolules 0–5 mm, distal 2/3–3/4 of margin incised 1/2–3/4, rarely +, to midvein, teeth (4–)5–8 per side, 4–5 mm, apical tufts 1 mm, abaxial surfaces gray to grayish white, long hairs abundant, cottony-crisped hairs usually dense, short hairs and glands absent or obscured, adaxial green to grayish green, long hairs sparse to common, 0.5–1.5 mm, stiff, short hairs absent or sparse, rarely common, crisped and cottony hairs absent, glands absent or sparse, rarely 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.
2–3.
10–80-flowered.
4–20-flowered, open, branch angle (10–)20–45°.
0.3–1.5(–2) cm.
0.5–3 cm, proximal to 5 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 linear to narrowly lanceolate, 3–4 × 0.8–1.2 mm;
hypanthium 4–6 mm diam.;
sepals 4–5 mm, apex subacute to acute, glands usually ± sparse, not obscured;
petals pale yellow, not overlapping, 5–7 × (4–)5–6.5 mm, distinctly longer than sepals;
filaments 0.5–1.5 mm, anthers 0.4 mm;
carpels 30–60, styles 0.9–1.1 mm.
0.8–1.1 mm, smooth to lightly rugose.
1.2 mm.
= 14, 28, 35, 42, 56, 62 (Eurasia).
= 56.
Potentilla argentea
Potentilla rubricaulis
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.)
As addressed by B. Ertter et al. (2013), the name Potentilla rubricaulis is here restricted to relatively large plants with open inflorescences occurring mainly in glaciated parts of subarctic northwestern Canada and Alaska. Plants from the Chugach Mountains of southern Alaska tend to be more conspicuously glandular than elsewhere.
The distinction between Potentilla rubricaulis and large forms of P. arenosa with supernumerary leaflets is problematic. Although both species have somewhat similar petiole vestiture (long, straight, verrucose hairs and a layer of short, stiff, or curly hairs), the latter species tends to have more stiffly spreading petiole hairs and prominently petiolulate central leaflets.
The octoploid chromosome count (P. M. Dansereau and E. Steiner 1956) from Great Bear Lake area, Northwest Territories, probably belongs to Potentilla rubricaulis in the narrow sense, since that is its type locality.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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