|The Acanthaceae are mostly herbs or shrubs comprising about 340 genera and 2,500 species, including twining forms. The leaves are simple, opposite and decussate; stipules are lacking. The flowers are bisexual, zygomorphic, and usually are associated with conspicuous, often brightly colored bracts. The calyx is usually deeply 4-5 lobed or sometimes is highly reduced with more numerous minute teeth. The corolla is sympetalous, usually 5-merous, mostly zygomorphic, and commonly 2 lipped. The androecium usually consists of 4 didynamous stamens or only 2 stamens adnate to the corolla tube or epigynous zone, alternate with the lobes. The gynoecium consists of a single compound pistil of 2 carpels, a single style, and a superior ovary with 2 locules, each with usually 2-10 axile ovules in one or two collateral vertical tiers. An annular nectary disk is usually found around the base of the ovary. The fruit is commonly an elastically dehiscent loculicidal capsule. The seed stalk or funiculus of each seed is modified into a hook shaped jaculator or retinaculum that functions in flinging out the seeds during dehiscence.
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