Annual or perennial herbs, trailing or branches erect. Leaves with membranous basal sheath, ciliate distally; petiole sessile or subsessile; lamina ovate or narrowly ovate, 2–12 cm long, 0.5–1.5(–3.0) cm wide, usually green, glossy. Inflorescence subtended by a spathe. Flowers zygomorphic; sepals green, unequal, the lower 2 sometimes fused; petals blue, delicate, unequal, the lower one reduced, often colourless; fertile stamens usually 3; staminodes (2–)3. Fruit a (2–)3 chambered capsule, usually with 3–6 seeds.
c. 170 species, mostly in tropical and subtropical regions of the world; c. 11 species in Australia, 1 in Victoria.
