Description from Flora of China Herbs annual or perennial. Stems
diffuse or procumbent, much branched. Leaves alternate or
opposite, sessile or shortly petiolate; leaf blade oblong,
elliptic, or subcordate; stipules small, membranous, caducous.
Inflorescence a small cyme or glomerule, sometimes reduced to a
solitary flower, leaf-opposed or terminal; bracts small,
membranous. Flowers 4- or 5-merous. Pedicel green, short or
nearly absent, small. Sepals not aristate at apex, persistent.
Petals very small or absent. Stamens as many as and shorter than
sepals. Ovary obovoid, 1-locular with 1 to several ovules; style
very short, apex 2-fid. Fruit a utricle, a membranous-walled
achene enclosed within persistent sepals, irregularly dehiscent
or indehiscent, usually 1-seeded. Seeds brown, ovoid or flat-
orbicular; testa shiny. About 45 species: Africa, Europe, and
Mediterranean region to C Asia; three species in China.
(Authors: Lu Dequan; Michael G. Gilbert)