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..
Trees or shrubs, with mostly opposite odd-pinnate or 3-foliolate stipulate leaves, and regular perfect flowers in terminal or axillary clusters. Sepals, petals and stamens usually 5. Carpels mostly 3. Disk large, the stamens inserted at its base without. Anthers introrse, 2-celled. Fruit a dehiscent bladdery capsule in the following genus, indehiscent in some others. Seeds solitary or few in each carpel; testa hard; endosperm fleshy; embryo straight.
About 5 genera, and 22 species, widely distributed.