Annual or perennial, monoecious or dioecious, herbs with climbing or prostrate stems. Leaves simple. Tendrils simple, simple at each node (except C. humifructus which has 2-8 at each node). Male flowers solitary or in few-flowered fascicles; female flowers solitary. Disk obvious, free from the receptacle-tube. Ovary smooth or bearing setae, spines or tubercles. Stamens 3, two 2-thecous, one 1-thecous.