Potentilla anserina subsp. pacifica

(Howell) Rousi

Ann. Bot. Fenn. 2: 104. 1965.

Common names: Pacific silverweed
EndemicIllustrated
Basionym: Potentilla pacifica Howell Fl. N.W. Amer., 179. 1898
Synonyms: Argentina occidentalis Rydberg A. pacifica (Howell) Rydberg P. anserina var. grandis Torrey & A. Gray P. egedei subsp. grandis (Torrey & A. Gray) Hultén P. egedei subsp. pacifica (Howell) L. A. Sergienko P. rolandii
Treatment appears in FNA Volume 9. Treatment on page 129. Mentioned on page 127, 128, 130.

Stems glabrous or sparsely hairy. Leaves erect, rarely horizontal or ascending, (3–)10–50(–75) cm; leaflets (4–)5–10(–15) per side, separate, rarely overlapping, teeth (4–)6–12(–16) per side, teeth apex acute to acuminate, rarely subacute, surfaces: abaxial with long hairs absent or sparse, on veins, cottony-crisped hairs dense, adaxial glabrous, rarely sparsely to densely hairy. Flowers 1–2.5(–3.5) cm diam.; epicalyx bractlets narrowly to broadly ovate-triangular, shorter than sepals, entire, rarely 2-fid or dentate; hypanthium patelliform (wider than deep) in fruit; petals not or rarely overlapping, elliptic; carpels (20–)50–200(–250). Achenes without dorsal groove. 2n = 28.


Phenology: Flowering summer.
Habitat: Salt and brackish marshes, clay and sandy seashores, maritime drift deposits
Elevation: 0–150 m

Distribution

V9 184-distribution-map.jpg

B.C., N.B., Nfld. and Labr., N.S., P.E.I., Que., Alaska, Calif., Conn., Maine, Mass., N.H., N.Y., Oreg., R.I., Wash.

Discussion

Pacific and Atlantic populations of subsp. pacifica are widely separated geographically but are essentially the same morphologically, except for the high number of achenes in some west coast populations.

Selected References

None.

Lower Taxa

None.
Reidar Elven +  and David F. Murray +
(Howell) Rousi +
Potentilla pacifica +
Pacific silverweed +
B.C. +, N.B. +, Nfld. and Labr. +, N.S. +, P.E.I. +, Que. +, Alaska +, Calif. +, Conn. +, Maine +, Mass. +, N.H. +, N.Y. +, Oreg. +, R.I. +  and Wash. +
0–150 m +
Salt and brackish marshes, clay and sandy seashores, maritime drift deposits +
Flowering summer. +
Ann. Bot. Fenn. +
Endemic +  and Illustrated +
Argentina occidentalis +, A. pacifica +, P. anserina var. grandis +, P. egedei subsp. grandis +, P. egedei subsp. pacifica +  and P. rolandii +
Potentilla anserina subsp. pacifica +
Potentilla anserina +
subspecies +