Annual or perennial herbs, rarely subshrubs. Leaves alternate, petiolate to sessile; ocrea brown, truncate, membranous, deciduous or persistent. Flowers bisexual, rarely bisexual and male, in axillary or terminal and upper axillary raceme-like or corymb-like panicles; perianth segments 5, petaloid, the outer smaller than inner, not enlarging in fruit; stamens 8; styles 3, stigmas capitate. Achene triquetrous to trigonous, exceeding perianth.
About 15 species from temperate Asia and Europe, 1 species naturalised in Australia.