Potentilla anserina
Potentilla reptans
common silverweed, Pacific cinquefoil, silver weed cinquefoil, silverweed
creeping cinquefoil, potentille rampante
soon becoming prostrate, flagelliform, not branched, rooting at some nodes, 1.5–10+ dm.
petiole (0.5–)1–15(–25) cm, long hairs absent or sparse to dense, 1.5–3.5 mm;
larger leaflets (0.4–)0.5–5(–7) × (0.2–)0.3–2(–3) cm, surfaces: abaxial with long hairs absent or sparse to abundant, not restricted to veins, 0.5–2(–2.5) mm, cottony-crisped hairs usually dense or usually absent (in subsp. groenlandica), adaxial with long hairs absent or sparse to abundant, cottony-crisped hairs usually absent, sometimes sparse to common (especially subsp. yukonensis).
persistent, usually palmate, 3–12(–30) cm;
petiole 2–10(–25) cm, long hairs sparse to abundant, tightly to loosely appressed, 0.5–1.5 mm, usually stiff, sometimes weak, glands absent;
leaflets (3–)5(–7), central oblanceolate to obovate, (0.5–)2–4(–7) × 0.3–1.5(–2.5) cm, distal ± 3/4 of margin incised 1/4–1/3 to midvein, teeth (3–)4–12 per side, surfaces similar, green, sparsely to moderately hairy.
2–3(–4) proximal to 1st flowering node, usually well expanded at anthesis, usually palmate, 2–8(–20) cm;
petiole 0.5–6(–15) cm;
leaflets (3–)5, ± resembling those of basal leaves, apex rounded to obtuse.
solitary flowers at stolon nodes.
(2.5–)4–12(–15) cm.
epicalyx bractlets narrowly to broadly ovate-triangular or linear to elliptic, (2–)2.5–7(–8) × (0.3–)0.5–3(–3.5) mm, often 2-fid or dentate;
sepals (3–)3.5–7(–9) mm, apex subacute to acuminate;
petals (4–)5–15(–20) × (2.5–)3–10(–12) mm;
filaments (1–)2.5–3.5(–4.5) mm, anthers 0.7–1.3 mm;
carpels (10–)20–200(–250).
5(–10)-merous;
epicalyx bractlets elliptic or oblong to ovate, 4–10 × 1.5–3.5 mm, often much larger than sepals (especially in fruit);
hypanthium 4–7 mm diam.;
sepals (3–)5–7 mm, apex broadly acute to obtuse;
petals 7–9(–12) × 6–9(–11) mm, apex usually ± retuse;
stamens ca. 20, filaments (0.5–)1–2.5(–2.8) mm, anthers (1–)1.3–2 mm;
carpels 60–120, styles 0.6–1.3 mm.
2 mm.
1.3–1.6 mm, ± rugose.
erect, slender to stout, 2–6+ cm.
= 28 (Eurasia).
Potentilla anserina
Potentilla reptans
Subspecies 4 or 5 (4 in the flora).
Potentilla anserina is polymorphic in most features, especially in hairiness, but also in size and in degree of dissection of leaflets, epicalyx bractlets, and sepals. While most of the variation described by A. G. Blytt (1906) is taxonomically insignificant, A. Rousi (1965) found support for three northern races: subspp. anserina, egedei, and pacifica. He also suggested that P. yukonensis Hultén might qualify as a separate subspecies. This treatment follows J. Soják (1994) in accepting four northern subspecies of P. anserina, all present in North America.
A. Rousi (1965) demonstrated partial interfertility between the races of Potentilla anserina, which form intermediates in all zones of contact. The distinctness of the four races, in spite of intermediates, is upheld by being partly allopatric and occupying different habitats where they are sympatric. As partly interfertile parapatric entities, they are best treated as subspecies.
The vast majority of chromosome counts are tetraploid. Tetraploid plants (2n = 28) are fully fertile; hexaploids (2n = 42) are largely pollen and seed sterile; pentaploids (2n = 35) are probably occasional hybrids (S. Erlandsson 1942, 1942b; A. Rousi 1965). A. Kurtto et al. (in J. Jalas et al. 1972+, vol. 13) considered numbers above tetraploid level as cases of occasional autopolyploidy.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Potentilla reptans is becoming widely introduced in North America, though not fully naturalized in some of the states indicated here. It may be confused with P. canadensis and P. simplex, but, in addition to the characters highlighted in the key, P. reptans tends to have more crenately toothed leaves than the more sharply toothed leaves of the native species. The plant has a history of medicinal uses similar to that of P. erecta. The cultivated double-flowered form is sometimes found established in weedy places.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Epicalyx bractlets equal to or longer than sepals, often 2-fid or dentate; leaflet surfaces: abaxial with cottony-crisped hairs dense, long hairs common to abundant, on and between veins, adaxial glabrous or sparsely to densely hairy; achenes with dorsal groove; inland and seashore plants | → 2 |
1. Epicalyx bractlets shorter than sepals, usually entire, rarely 2-fid or dentate; leaflet surfaces: abaxial with cottony-crisped hairs absent or sparse to dense, long hairs absent or sparse, on veins, adaxial usually glabrous, rarely sparsely to densely hairy; achenes without dorsal groove; seashore or near-coastal plants | → 3 |
2. Hypanthium patelliform (wider than deep) in fruit; epicalyx bractlets narrowly to broadly ovate-triangular, equal to sepals; most of North America. | subsp. anserina |
2. Hypanthium turbinate (± as deep as wide) in fruit; epicalyx bractlets usually linear to elliptic, longer than sepals, rarely subequal; interior w Canada and Alaska. | subsp. yukonensis |
3. Carpels (20–)50–200(–250); leaves (3–)10–50(–75) cm; leaflets (4–)5–10(–15) per side, abaxial surfaces densely hairy, teeth (4–)6–12(–16) per side, teeth apices acute to acuminate, rarely subacute; flowers 1–2.5(–3.5) cm diam. | subsp. pacifica |
3. Carpels 25–60; leaves (1–)2–10 cm, rarely longer; leaflets 2–4(–5) per side, abaxial surfaces glabrous, sometimes sparsely to densely hairy, teeth 2–6(–10) per side, teeth apices rounded to subacute; flowers 0.8–1.5 cm diam. | subsp. groenlandica |
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
IL Wildflowers, 
MI Flora, 
MN Wildflowers, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
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- Local floras: BC, OR
- Local Web sites: CalFlora, CalPhotos, Flora NW,
Go Botany, IL Wildflowers, 
LA Plants, 
MD Biodiversity, MI Flora, MN Wildflowers, PNW Herbaria - WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
