in botany, a genus of the monocia monandra clasps. The calyx of the male is divided into two parts; it has no corolla; and the filament is long. The calyx of the female consists of two leaves connected to the germen; it has no corolla; the stigmas are two; and the seeds are biconvex and compressed. There is but one species, viz. the arenarius, a native of Tartary.