Erect herbs or subshrubs. Pedicels articulated and densely covered with stellate hairs. Flowers solitary in the leaf axils or aggregated into a panicle. Epicalyx absent. Calyx 5 lobed, costae absent. Corolla yellow-orange or lavender, often drying bluish, 2-3 times the length of calyx. Staminal column antheriferous at apex. Fruits schizocarpic. Styles and mericarps 6-11. Mericarps flaring apically, usually with 2 prominent apical wings (except in H. exalata), divided into 2 cells by a medial constriction, with a solitary seed in the basal and usually 1-2 seeds in the upper part (except H. exalata which has a single seed). Endoglossum present.