ARCTOPUS, in botany, a genus of the polygamia diœcia class. The umbella of the male is compound; the involucrum consists of five leaves; the corolla has five petals; the stamens are five; and two pistils: The umbella of the hermaphrodite is simple; the involucrum is divided into four parts, is spinous, large,
and contains many male flowers in the disk. There is but one species of arctopus, viz. the echinatus, a native of Ethiopia.