Acanthus

Subshrubs, shrubs or small trees. Leaves pinnatifid or lobate to rarely entire, margin often spiny. Inflorescences +/-dense, short to long terminal spikes; bracts and bracteoles present. Calyx divided to base into 4 sepals; anterior and posterior sepal much larger than lateral ones. Corolla 1-lipped; tube very short; anterior lip 3-5-lobed with middle lobe outside in bud; posterior lip represented by a thickened sinus at level of insertion of stamens. Androecium : stamens 4, +/-equal; filaments glabrous; anthers 1-thecous, oblong, muticous, fringed with white hairs. Gynoecium : ovary 2-locular, with 2 ascending ovules per locule; style mostly glabrous, bifid at apex. Capsule ellipsoid, woody, shiny brown, 2-4-seeded. Seeds discoid, glabrous.