Potentilla argentea
Potentilla litoralis
hoary cinquefoil, potentille argentée, silver cinquefoil, silver-leaf cinquefoil, silvery cinquefoil
coast cinquefoil, Pennsylvania cinquefoil, potentille du littoral
mostly decumbent to ascending, 1–6 dm.
decumbent to nearly erect, (0.4–)1–4.5(–6) dm.
palmate.
subpinnate to subpalmate, (3–)4–15(–25) cm;
petiole (1–)2–8(–15) cm, long hairs sparse to abundant, appressed to rarely ascending, ± 1 mm, ± stiff, short hairs absent or sparse, cottony or crisped hairs absent, glands ± sparse;
leaflets 2–3 per side, on distal 1/6–1/3(–1/2) of leaf axis, ± overlapping, terminal ones narrowly lanceolate to narrowly obovate, (1.5–)2–5(–7) × 1–2.5 cm, margins revolute, incised 3/4+ to midvein, undivided medial blade 2–10 mm wide, teeth (2–)5–8 per side, ± linear-elliptic, surfaces usually ± dissimilar, abaxial green to grayish, long hairs ± abundant especially on veins, 0.5–1.5 mm, weak, short hairs absent or sparse, cottony hairs absent, crisped hairs absent or sparse to abundant, glands ± abundant, adaxial ± green, long hairs sparse to common, ± appressed, 0.5–1.5 mm, short hairs absent or sparse, cottony hairs absent, crisped hairs absent or sparse, 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–)2–4.
10–80-flowered.
(1–)5–30-flowered, congested, scarcely lengthening in fruit.
0.3–1.5(–2) cm.
0.2–1 cm (proximal to 3 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 narrowly, rarely broadly, elliptic to linear, 2.5–5(–6) × 1(–2) mm, lengths ± 2/3 to equal to sepals, margins ± revolute (at least in fruit);
hypanthium 3–5 mm diam.;
sepals 3–6 mm, apex ± acute, abaxial surfaces: venation moderate, glands abundant, evident at least distally;
petals yellow, 3–5 × 2–4 mm, lengths ± equal to sepals;
filaments (0.5–)1–1.5 mm, anthers 0.3–0.5 mm;
carpels 50–100, styles papillate-swollen in proximal 1/2–3/4+, 1–1.5 mm.
0.8–1.1 mm, smooth to lightly rugose.
± 1 mm, smooth to faintly rugose.
= 14, 28, 35, 42, 56, 62 (Eurasia).
= 28, 56.
Potentilla argentea
Potentilla litoralis
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.)
Revolute epicalyx bractlets and visible glands on the sepal tips are the most reliable characteristics to distinguish Potentilla litoralis from P. bipinnatifida where their ranges overlap in the northern Great Plains. The former is also more likely to be decumbent-ascending and tends to darken more in drying. Intermediates occur, as well as possible hybrids with P. bimundorum, P. hippiana, and P. pensylvanica.
Rydberg described Potentilla litoralis to accommodate the coastal phase of this species, concentrated around the Gulf of St. Lawrence and along the north Atlantic Coast as far south as New Hampshire. Potentilla pectinata Rafinesque was briefly adopted as the older name (for example, Frère Marie-Victorin 1935); it is both superfluous and a later homonym (B. Boivin 1952). The homotypic synonyms P. pensylvanica var. glabrata (Lehmann) S. Watson, P. bipinnatifida var. glabrata (Lehmann) Kohli & Packer, and P. glabrella Rydberg have been misapplied to P. litoralis; the type is a specimen of P. ovina var. ovina (sect. Multijugae) (J. Soják 1996). The type of P. dissecta Pursh, traditionally applied to P. glaucophylla (sect. Graciles), is closest to this species but has palmate leaves; ambiguity has led to the name being rejected (B. Ertter et al. 2008).
The current circumscription of Potentilla litoralis includes prairie populations extending through the northern Great Plains and boreal regions into eastern Alaska; those plants have generally been called P. virgulata when not combined with P. bipinnatifida, P. multifida in the broad sense, or P. pensylvanica. Outlying populations occur at least as far south as Wyoming (including the type of P. virgulata), central Nevada (possibly as introductions), and, possibly, Colorado.
Other than the tendency of prairie plants to be somewhat larger and more erect than the coastal plants, no significant morphologic distinctions have been found to match the differences in habitat and distribution. Based on their distribution map, B. L. Kohli and J. G. Packer (1976) considered the coastal and prairie populations, as well as what is here separated as Potentilla jepsonii, to comprise a single taxon, which they called P. bipinnatifida var. glabrata (Lehmann) Kohli & Packer (misapplied).
If Potentilla litoralis is treated as a variety of another species, var. virgulata has priority at varietal rank.
Unequivocal Potentilla litoralis barely enters Alaska; the majority of collections from central, western, and northern Alaska previously placed in P. litoralis represent an undescribed taxon whose dimensions are not included in the preceding description. Significant differences include more deeply incised leaflets with fewer teeth, flat, linear epicalyx bractlets, and larger petals. Some collections from around Kotzebue with relatively wide sepals and sparse glands may indicate hybridization with P. bimundorum.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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