Acanthaceae

Leaves : Leaves are usually simple and opposite, stipules
absent.Stems: In herbaceous species, stems are cylindrical or quadrangular,  In lianas, stems are cylindrical. Flowers: Flowers are bisexual, zygomorphic (having only one plane of symmetry, as in a pea), bracteate, and bracteolate. The calyx usually has four or five lobes, and the corolla is tubular, two-lipped, or five-lobed. Fruit: The fruit is a two-celled capsule that dehisces somewhat explosively. Seeds: In most species, seeds are attached to a small, hooked stalk called a jaculator or a retinaculum. This stalk ejects the seeds from the capsule.