Description from Flora of China
Herbs, annual or perennial, without stinging hairs. Leaves alternate; stipules absent; leaf blade 3-veined or triplinerved, margin entire; cystoliths punctiform. Inflorescences axillary, clusters or cymes of unisexual or bisexual flowers (plants monoecious); bracts calyxlike. Bisexual flowers: perianth lobes 3 or 4, linear, valvate. Male flowers: perianth lobes 3 or 4; rudimentary ovary minute. Female flowers: perianth lobes 3 or 4, connate to a tube at base, much shorter than male lobes. staminodes absent. Ovary straight, free from perianth; style short or absent; stigma penicillate or spatulate; deciduous, ovule orthotropous. Achene ovoid, slightly compressed, with lustrous and crustaceous pericarp, enclosed by dry persistent perianth. Seeds with endosperm; cotyledons oblong-ovate.
About 20 species: temperate and subtropical regions; one species in China.
(Authors: Chen Jiarui (陈家瑞 Chen Chia-jui); Ib Friis, C. Melanie Wilmot-Dear)