Potentilla L.
(C.J.W., D.R.G.)
Short-stemmed, perennial or rarely annual or biennial herbs or small shrubs, often mat-forming or sprawling and spreading, not armed. Lvs in basal rosettes or cauline or both, pinnate or palmate; leaflets usually dentate or crenate; stipules free in upper part, ± connate at base, persistent. Infl. a cyme or fls solitary, usually terminal. Fls small- to medium-sized, ⚥, (4)-5-merous. Hypanthium ± flat or weakly concave, with a central, hemispheric dry or spongy receptacle (carpophore). Epicalyx segments lobed or entire. Calyx usually with triangular to lanceolate sepals. Petals ± obovate, usually white or yellow, rarely reddish, orange or purple. Stamens (10)-20-numerous. Ovary superior; carpels (4)-10-80; styles surrounded by hypanthium rim; ovules 1 per carpel. Fr. a head of 4-many achenes on surface of dry and spongy hypanthium; styles usually deciduous at fruiting.
Key
c. 300 spp., widespread in N. temperate and arctic regions, extending to alpine zones and S. temperate regions. Native sp. 1, naturalised 6.
Some members of the genus are cultivated as garden ornamentals; others are agricultural pests especially in drier, temperate or Mediterranean regions. The commonest sp. in cultivation in N.Z. is P. fruticosus L. which is easily distinguished from the wild spp. as it is a small woody shrub with entire leaflets. The common name cinquefoil (referring to the commonly 5-foliolate lvs) is frequently given to weedy spp.
