This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", 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, resin-bearing except Taxus. Leaves evergreen or deciduous, linear, or in several exotic genera broad or sometimes fan-shaped, the pollen-sacs and ovules borne in separate clusters or solitary. Perianth wanting. Stamens much as in the Pinaceae. Ovules with either one or two integuments; when two, the outer one fleshy, when only one, its outer part fleshy. Fruit drupe-like or rarely a cone.
About 10 genera and 75 species, of wide geographic distribution, most numerous in the southern hemisphere. The Maiden-hair Tree, Ginkgo biloba, of China and Japan, with fan-shaped leaves, is an interesting relative of the group, now much planted for ornament.