Poterium Linnaeus.

Herbs perennial. Rootstock robust, bearing many fusiform, cylindric roots in lower part. Stipules sheathing, adnate to petiole, petiole sheathing and imbricate at base; leaf blade imparipinnate; leaflets serrate at margin. Inflorescences terminal on elongate scapes, densely capitate or spicate, bracteate and bracteolate. Flowers bisexual, rarely unisexual (when plants monoecious). Hypanthium with a constricted throat. Sepals 4(–7), imbricate, petaloid, purple, red, pink, or white, rarely greenish. Petals absent. Disk lining hypanthium. Stamens usually 4, rarely more, inserted in throat of hypanthium; filaments free, rarely partly connate; anthers didymous. Carpel 1(or 2), included in hypanthium; ovule pendulous; style terminal, filiform; stigma penicillate. Achene dry, included in hardened, muricate or winged hypanthium. Cotyledons planoconvex. x = 7.

About 30 species: Asia, Europe, North America; seven species (one endemic) in China.

(Authors: Li Chaoluan (Li Chao-luang); Hiroshi Ikeda, Hideaki Ohba)