ZINNIA, in botany; a genus of plants of the class syngenesia, order polygamia superflua; and in the natural system arranged under the 49th order, Composita. The receptacle is paleaceous, the pappus consists of two erect awns, the calyx is ovato-cylindrical and imbricated; the rays consist of five peristylar entire florets. There are two species, the pauciflora and multiflora, neither of which is a native of Britain.