Description from Flora of China
Herbs perennial, tall, with creeping rhizome. Leaves stipulate, imparipinnate. Flowers usually in terminal, spikelike racemes, bisexual, rather small. Hypanthium turbinate, sulcate, with hooked prickles or 5 teeth below limb abaxially, constricted at throat. Sepals 5, imbricate, persistent. Petals 5, larger than sepals. Disk lining hypanthium, margin thickened, annular, glandular. Stamens 5–15 or more, inserted at mouth of hypanthium, 1-seriate. Carpels usually 2, included in hypanthium, sessile; ovule pendulous; style terminal, exserted, filiform; stigma dilated. Achenes 1 or 2, included in closed hypanthium, distally with hooked prickles. Seed pendulous; testa membranous. x = 7.
About ten species: N temperate zone, alpine regions of tropics; four species in China.
(Authors: Li Chaoluan (Li Chao-luang); Hiroshi Ikeda, Hideaki Ohba)