Description from Flora of China
Herbs perennial, rarely biennial, annual, or shrubs, if perennial then with ± tufted, scaly rootstock. Stems erect, ascending, or prostrate. Leaves pinnate or palmately compound; stipules ± adnate to petiole. Inflorescence often cymose or cymose-paniculate, or 1-flowered. Flowers usually bisexual. Hypanthium concave, mostly hemispheric. Sepals 5, valvate; epicalyx segments 5, alternating with sepals. Petals 5, often yellow, rarely white or purple. Stamens usually ca. 20 in 3 series of 10, 5, and 5, rarely fewer or more (11–30); anthers 2-loculed. Carpels usually numerous, free, inserted on slightly elevated receptacle; ovule ascending or pendulous, anatropous, amphitropous, or suborthotropous; style subterminal, lateral, or basal. Achenes numerous, inserted on dry receptacle with persistent sepals. Seed testa membranous. x = 7.
About 500 species: mostly in temperate, arctic, and alpine zones of the N hemisphere, a few in the S hemisphere; 86 species (22 endemic) in China.
(Authors: Li Chaoluan (Li Chao-luang); Hiroshi Ikeda, Hideaki Ohba)