in botany: A genus of the monogynia order, belonging to the tetrandria clas of plants. There is no calyx; the corolla consists of four linear oblique petals; the stamens are four very short filaments; the anthers are pretty large, oblong, and seated within the cavity of the petal. The pericarpium is a round unilocular follicle, sharpened at both ends; the seeds are four or five in number, egg-shaped, and compressed.