This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", 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..
Vines, climbing by tendrils, or erect herbs, with alternate petioled usually palmately-lobed leaves, and solitary or clustered perfect regular flowers. Calyx-tube short or elongated, persistent. Petals usually 5, inserted on the throat of the calyx, distinct, or in some species united. Stamens 5. Throat of the calyx crowned with a double or triple fringe. Filaments subulate or filiform, monadel-phous, or separate. Ovary free from the calyx, I-celled; placentae 3-5, parietal; styles 1-5. Fruit a berry or capsule, usually many-seeded.
About 18 genera and 350 species, of warm and tropical regions, most abundant in South America.