Acanthus from the Greek akanthe for thorn, referring to the spiny leaves and bracts present in many species. The Acanthaceae are chiefly herbs although there are shrubs and vines (twine clockwise), but very few form trees. Leaves are usually opposite and cystoliths are commonly found in the leaves of many species. Bracts and bracteoles are common, often coloured; corolla is usually irregular, sometimes bilabiate, petals fused 4-5, stamens 2-4 rarely 5, staminodes maybe present. Ovary of 2 carpels, fruit a capsule, seeds usually attached to a hooked projection which assists in dispersal (absent in Thunbergia). Fruit dehiscence explosive. Many ornamentals, many are weeds or potential weeds.