Trailing to erect or climbing perennial subshrubs. Leaves opposite, terete, semi-terete, compressed or trigonous, densely papillose, the papillae blister-like or acute. Flowers solitary, pedicellate, terminal on main branches and small side-shoots; sepals 5, subequal; petaloid staminodes numerous in 1 or 2 series; ovary inferior, 4–6-locular, flat or convex at top with grouped glands; styles 4–6; ovules numerous, parietal. Fruit a 5-locular capsule; valves winged; locules remaining partly covered by an elastic, membranous 'roof'; seeds ribbed or tuberculate.
About 95 species, all from South Africa, mostly from the Cape Province; 1 species naturalised in Australia.