Rigid, spiny dendroid-stellate pubescent annuals, with alternate flat, spine-tipped leaves. Flowers in axillary-cymes, bracteate, forming capitate or oblong-obovoid spiny glomerules borne in the axils of nearly all leaves. Perianth of (0-) 1-3 (-5) scarious segments. Stamens 1-5. Ovary with 2 stigmas. Fruit strongly flattened, opening at maturity at the front and back by means of scarious winglets, terminating in a long 2-cleft or 3-pronged beak. Seeds vertical, oval, compressed with semi-transparent endosperm; embryo circular.