Description from Flora of China
Herbs perennial (rarely annual), with woody rhizome. Stems decumbent to erect. Leaves stipulate, long petiolate; stipules adnate to sheathing petiole; leaf blade simple, ± orbicular, margin lobed, digitate, or palmately parted. Inflorescences usually dense corymbs, rarely lax cymes or a solitary flower, ebracteate. Flowers very small, bisexual. Hypanthium urceolate, persistent, with constricted throat. Sepals 4(or 5), valvate; epicalyx segments 4(or 5), alternating with sepals. Petals absent. Disk lining hypanthium, margin thickened. Stamens (1–)4; filaments free, short. Carpel 1(–4), sessile or substipitate, free; ovule ascending from base of locule; style basal or adaxial, filiform, glabrous; stigma capitellate. Achene 1(–4), enclosed in membranous hypanthium. Seed basal; testa membranous; cotyledons cylindric-obovoid. x = 8.
Between 100 and 300 species: frigid and temperate regions of Africa, Asia, Europe, and America, extending to alpine areas in the tropics; three species in China.
(Authors: Li Chaoluan (Li Chao-luang); Hiroshi Ikeda, Hideaki Ohba)