Acanthaceae  

Usually perennial, shrubby or spinescent or spiny herbs or shrubs, rarely climbers or trees, rarely annual. Leaves exstipulate, petiolate or sessile, opposite-decussate, undulate-dentate, sometimes crenate-dentate or lobed. Inflorescence cymose or racemose or lax to dense spicate or paniculate, rarely solitary. Flowers sessile or pedicellate, often large, 5 or 4-merous, usually zygomorphic, bisexual, hypogynous; with 1-2 or more bracts, the bracts often prominent, frequently coloured, imbricate, peristent, occasionally absent. Calyx 4-5-lobed, sometimes very small, tubular dentate or spinescent or truncate. Corolla-tube cylindrical to ventricose; limb spreadingly 5-lobed to strongly 2-lipped; the upper lip entire or 2-fid, sometimes missing or fimbriate; lower lip 3-fid to 3-lobed. Stamens 4, didynamous, or 2, rarely 5; epipetalous; staminodes 0-1-3; anthers dithecous or monothecous; the anther-cells parallel, divergent or superposed. Gyanaecium bicarpellary, syncarpous. Ovary often borne above a hypogynous nectariferous disc, 2- celled, conical to oblong-cylindrical; ovules 2-10, rarely more per chamber; style single, filiform, stigmas usually 2. Fruit a capsule; the capsule stipitate or sessile, compressed or terete, clavate to oblong- cylindric, usually elastically dehiscent from apex downwards. Seeds usually flattened, lenticular or discoid rarely globose, usually borne on hook-like funiculare ejaculators; testa smooth or rugose to echiniate, often sticky on wetting.