Monoecious annual herbs, stellate-dendroid hairy with forked branches and linear to oblong, narrow, entire leaves; the lower usually broader than the upper ones. Staminate flowers ebracteolate, in groups of 2-5, mostly in the axils of upper leaves, shortly pedicellate with a 2-lobed perianth and 1 stamen. Pistillate flowers solitary, without perianth, with a hairy ovary and 2 long filiform stigmas, enclosed by 2 united obcuneate or obovate involucral bracteoles; fruiting bracteoles terminated by 2 long, acute, straight, spreading aculeiform spines.