Fls regular, perfect, us. in cymes; calyx us. 4-5-lobed or of separate sepals; petals same number as sepals, free or ± united; stamens same number as petals, or twice as many, anthers introrse; carpels same number as petals, free or united at base, us. each subtended by a nectariferous scale. Ovules us. many (few in Tillaea); frs of follicles with minute seeds; embryo straight, endosperm us. fleshy. Herbs or subshrubs, mostly succulent, with exstipulate opp. or alt. lvs. Subcosmopolitan with over 30 genera and c. 1300 spp.

Annual or perennial herbs, sometimes small shrubs, with vegetative organs and often floral parts ± succulent, often reproducing by offsets or rhizomes. Stems prostrate to erect, sometimes with bulbils formed on them. Lvs opposite or alternate, usually simple, occasionally pinnate; stipules 0. Infl. usually variously cymose, often with many branches, sometimes paniculate; bracts usually ± persistent, sometimes caducous; fls actinomorphic, usually ☿, rarely unisexual (spp. dioecious), (3)-4-20-(32)-merous, often secund. Sepals equal or unequal, free or connate, sometimes forming a tube. Petals free or connate, occasionally forming a tube. Stamens somewhat perigynous, as many as or twice as many as the petals, if twice petals then outer whorl antipetalous; anthers 2-locular, dehiscing longitudinally. Ovary superior; carpels free, as many as petals, 1-locular; ovules usually many, rarely few; styles free, usually prominent. Nectary scales usually present at base of carpels, sometimes 0. Fr. usually a group of follicles, sometimes a capsule, membranous or coriaceous, often surrounded by the persistent corolla. Seeds very small; endosperm usually present, sometimes 0.