GEROPOGON, in botany: A genus of the polygamia æqualis order, belonging to the syngensia class of plants; and in the natural method ranking under the 49th order, Compositeæ. The receptacle is paleaceous, with the points of the paleæ sharp or bristly; the calyx is simple; the seeds of the disc have a feathered pappus; those of the radius have a pappus of five awns.