Fls bisexual, solitary or in a simple or bifid cincinnus, actinomorphic (occ. zygomorphic). Per. petaloid, tube campanulate to urceolate, lobes in 2 whorls of 3, one or both sts lacking. Stamens 3 or 6; anther sessile on per.-tube and dehiscing laterally and horizontally, or with short filaments and pendent within the tube and dehiscing longtiudinally; connective broad, sts elaborately lobed. Ovary inferior, 1–3-locular; ovules ∞, anatropous with 2 integuments, funicle often long; style simple; stigmas 3. Fr. us. capsular, sts fleshy; dehiscence various. Seeds minute. Annual or perennial herb, green and autotrophic or saprophytic and often colourless. Lvs alt., entire, simple, exstipulate, linear where not reduced to scales. Genera 10–20 according to views of different authors. Widely distributed in tropics but extending both north and south in both hemispheres.