Erect, annual herbs to undershrubs, densely stellate pubescent, sometimes mixed with simple hairs. Leaves variable in shape and size, angular or lobed or parted, usually with a nectary on the midrib beneath. Flowers axillary, usually solitary, sometimes fascicled; sessile to short pedicelled. Epicalyx segments 5 fused to the middle or above, adnate to calyx. Calyx 5-toothed. Petals 5. Staminal tube with nearly sessile anthers below the apex. Carpels 5 ovary 5-celled; style branches 10. Mericarps 5, indehiscent, with or without glochidiate spines.