in botany: A genus of the digynia order, belonging to the pentandria class of plants. The calyx is an involucrem, with about five linear leaves; the corolla consists of five oval-lanceolate petals; the stamens are five filaments; the anther roundish; the pericarpium an ovato-truncated fruit, with eight striae; there are two striated seeds, in some places plane, and in others convex.