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..
Erect or climbing shrubs, or small trees, often thorny. Leaves simple stipulate, mainly alternate, often 3-5-nerved. Stipules small, deciduous. Inflorescence commonly of axillary or terminal cymes, corymbs or panicles. Flowers small, regular, perfect or polygamous. Calyx-tube obconic or cylindric, the limb 4-5-toothed. Petals 4-5, inserted on the calyx, or none. Stamens 4-5, inserted with the petals and opposite them; anthers short, versatile. Disk fleshy. Ovary sessile, free from or immersed in the disk, 2 - 5- (often 3-) celled; ovules 1 in each cavity, anatropous. Fruit a drupe or capsule, often 3-celled. Seeds solitary in the cavities, erect; endosperm fleshy, rarely none; embryo large; coryledons flat.
About so genera and 600 species, natives of temperate and warm regions.
Ovary free from the disk; fruit a drupe.
Petals sessile, entire; stone of the drupe 2-celled.
Petals short-clawed or none; stones of the drupe 2-4.
Ovary adnate to the disk at its base; fruit dry.