This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
A large order of ornamental shrubs and trees, often aromatic. Leaves alternate, rarely opposite, usually entire, exstipulate, frequently furnished with immersed pellucid dots. Flowers generally small and inconspicuous, unisexual or bisexual, arranged in sessile clusters or umbellate or paniculate. Perianth inferior, 4- to 6-lobed. Stamens definite; anthers opening by
2 or 4 longitudinal valves. Fruit a 1-celled 1-seeded berry or drupe; seed pendulous. There are about 50 genera and 450 species, common in sub-tropical regions of Asia and America. Few hardy species are known.