Description from Flora of China
Herbs paludose or aquatic, perennial or under unfavorable conditions annual. Stems erect or creeping. Leaves radical from vegetative stem, solitary from flowering stems, curvinerved. Inflorescences racemose or subumbelliform, enveloped in broad leaf sheaths when young; peduncle bracteate at base; bract large. Flowers subsessile or shortly pedicellate; perianth segments free nearly to base, spreading during anthesis and afterward spirally contorted, inner segments wider than outer. Stamens 6, inserted at base of perianth, dimorphic: 1 with filament long, laterally with an erect, oblique tooth, anther basifixed, blue, large; other 5 subequal, anthers basifixed, yellow, small. Ovary 3-loculed; ovules numerous per locule. Style filiform; stigma subentire or minutely 3-lobed. Capsule loculicidal, 3-valved. Seeds small, longitudinally winged, transversely striate.
Eight species: tropical and subtropical Africa, Asia, and Australia; four species in China.