Potentilla norvegica is an annual or short-lived perennial herb, from a simple root, to 60 cm tall stout, hairy, leafy, branched, often red in full sun, stipules wing-shaped at base of leaf stalk.
Leaves alternate, 3-parted, leaflets widest above middle, to 8 cm, hairy, green on both sides, margin coarsely toothed, lower leaves stalked, upper leaves stalkless.
Flowers yellow, to 1 cm wide, 5 petals, calyx lobes slightly longer than petals, in tight clusters; self-fertile (agamospermy), (Mulligan and Kevan 1973); inflorescence branched, leafy; blooming and fruiting June-Oct. (Hough 1983).
Fruit dry, a head of achenes, covered by enlarged calyx; seeds numerous 0.1 cm, pale brown, shallowly ridged.
Wetland status: FACU.
Frequency in NYC: Infrequent.
Origin: Native and European.
Habitat: Open areas, roadsides, fields.
Note: Attacked by the fungi; Fabraea dehnii, Marssonina potentillae, Peronospora potentillae, Phoma potentillica, among others (Werner and Soule 1976).