This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Climbing, annual or perennial, mostly glabrous vines, with forked or simple tendrils, usually digitately compound leaves and small white or greenish monoecious flowers. Calyx cup-shaped, 5-toothed. Corolla rotate, deeply 5-parted. Staminate flowers racemose or pani-cled, the stamens united into a central column; anther 1, annular in our species. Pistillate flowers solitary; ovary obliquely ovoid, beaked, 1-3-celled, with 2 ovules in each cavity; style short; stigma large, hemispheric. Fruit spiny, obliquely ovoid, beaked, at length irregularly dehiscent, few-seeded. [Greek, circle-anther.]
About 40 species, natives of America. Type species: Cyclanthera pedata Schrad.
Annual; stem grooved and angular, glabrous, branching, climbing to a height of 3°-4°, or straggling. Petioles 1-2' long; leaves digitately 3-7-foliolate, the leaflets oval or oblong, usually acute at each end, ¥-2' long, rough on both sides, dentate, or somewhat lobed; staminate flowers racemose, borne on a peduncle ¥-2' long; pistillate flowers solitary, very short-peduncled; fruit narrowed at the base, slightly oblique, about 1' long, armed with slender spines.
Thickets, Kansas to Texas, Louisiana and northern Mexico. July-Sept.