Description from Flora of China
Herbs perennial. Rhizomes robust, short. Stems simple, erect, 4-angled. Leaves opposite, petiolate, exstipulate; leaf blade palmately lobed, papery. Inflorescences terminal or axillary, cymose. Flowers bisexual. Calyx tube adnate to ovary; lobes 5. Petals 5, inserted at base of calyx tube, alternate with calyx lobes. Stamens 15, 3-seriate, outermost series longest, innermost one shortest; filament slightly adnate to petal base; anthers medifixed, dehiscing laterally. Ovary semi-inferior, 3- or 4-loculed; placentation axile; ovules numerous, many seriate, flattened. Styles 3 or 4, free, filiform; stigma capitate. Fruit a capsule, dehiscing loculicidally. Seeds numerous, flat, surrounded by an oblique wing; endosperm fleshy; embryo straight; cotyledons ovate.
Two species: China, Japan, Korea; one species in China.
(Authors: Huang Shumei (Hwang Shu-mei); Bruce Bartholomew)