Fls in cymes or solitary, minute and greenish, hermaphrodite. Sepals 4 or 5 from rim of urceolate perig. cup; petals 0; stamens 1-10; ovary 1-celled with 1basal ovule (occ. 2); styles 2, free to base, stigmas 2; fr. an ind. 1(-2)-seeded nutlet enclosed within hardened perig. cup and persistent sepals; seed smooth, lenticular. Annual to perennial, us. densely branched, herbs with small, subulate, opp., connate, exstipulate lvs. Number of spp. variously estimated at from 10 to 150 in Europe, Asia, Africa, S. America, Australia, New Guinea and N.Z. Relationships of N.Z. and Australian forms need clarifying.

Annual, biennial or perennial herbs. Lvs opposite, exstipulate, linear to subulate, connate by narrowly scarious bases. Fls solitary or paired or clustered, on long axillary peduncles or not pedunculate; bracts small, scarious or leaflike; epicalyx 0. Sepals 4-5, inserted on rim of flask-shaped perigynous zone. Petals 0. Stamens 1, 2 or 5-10, inserted on rim of perigynous zone. Styles 2. Fr. a 1-seeded indehiscent nutlet, with perigynous zone and calyx adhering to fr. and falling with it when ripe. Seeds ovoid or ellipsoid, smooth, not winged.