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..
Climbing, woody vines, or erect shrubs, with copious watery sap, nodose joints, alternate simple or compound petioled leaves with deciduous stipules, and small regular greenish perfect or polygamo-dioecious flowers, in panicles, racemes or cymes. Calyx entire or 4-5-toothed. Petals 4 or 5, separate or coherent, valvate, caducous. Stamens 4 or 5, opposite the petals; filaments subulate, inserted at the base of the disk or between its lobes; disk sometimes obsolete or wanting; anthers 2-celled. Ovary I, generally immersed in the disk, 2-6-celled; ovules 1 or 2 in each cavity, ascending, anatropous. Fruit a 1-6-celled berry (commonly 2-celled). Seeds erect; testa bony; raphe generally distinct; endosperm cartilaginous; embryo short.
About 10 genera and over 500 species, widely distributed.
Hypogynous disk present, annular or cup-shaped, lobed or glandular; leaves not digitately com-noiind in our species.
Petals united into a cap, falling away without separating.
Petals separate, spreading.
Foliage not fleshy; flowers mostly 5-parted; shrubs or vines.
Foliage fleshy; flowers mostly 4-parted; vines.
Hypogynous disk obsolete or wanting; leaves digitately compound in our species, the leaflets 5-7.