Acanthaceae
Herbs, sometimes subshrubs or shrubs, annual or perennial, usually aromatic. Stems and branches usually 4-angled. Leaves opposite, rarely whorled or alternate, simple to pinnately dissected or compound, without stipules. Inflorescences generally compound, sometimes flowers solitary and axillary; verticillasters 2- to many flowered, subtended by leaves or bracts. Flowers bisexual, zygomorphic, rarely subactinomorphic, bracteolate or not. Calyx persistent, 5-toothed, 2-lipped; upper lip 3-toothed or entire (deciduous in Scutellaria); lower lip 2- or 4-toothed; tube sometimes hairy annulate inside. Corolla limb usually 2-lipped; upper lip 2-lobed and lower 3-lobed, rarely upper lip entire and lower 4-lobed, also rarely limb (4- or) 5-lobed; tube hairy annulate inside. Stamens epipetalous, 4 or 2, free, rarely filaments connate, sometimes one staminodial; anther 1- or 2-celled, usually dehiscing longitudinally; disc persistent. Ovary superior, 2-celled and each cell 2-ovuled and style subterminal, or ovary 4-parted and each lobe 1-ovuled and style gynobasic (from bases of ovary lobes) with 2-cleft apex. Fruit usually 4 dry nutlets. Seeds with or without endosperm.