Small, annual or perennial herbs. Leaves exstipulate, sessile or petioled, glabrous or pubescent with simple or stellate hairs. Inflorescences in lax, dichotomous cymes. Flowers hypogynous or slightly perigynous. Sepals (4 or) 5, free, herbaceous, usually 3-nerved. Petals (4 or) 5, rarely ab-sent, white, usually bifid, almost to the base. Stamens (3-)5 or 10, rarely more or absent. Ovary unilocular; Fruit a capsule opening by 4-6 valves. Seeds mostly numerous, rarely few to 1, reniform or spherical, rugose or verrucose.
Cosmopolitan: present Eurasian mountains: present
Between 150 and 200 species, with their main distribution in Eurasian mountains; some cosmopolitan.
The genus is still lacking a modern taxonomic revision. An unpublished study by J.F. Veldkamp (L) and Indonesian students from Herbarium Bogoriense (BO) and University Padjadjaran, Bandung (FMIPA) has been a great help in the revision of this genus.