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..
Monoecious or dioecious trees, shrubs or perennial herbs, with alternate or opposite simple mostly evergreen leaves, the sap not milky. Flowers clustered or solitary, regular, bracted, with or without a perianth (calyx). Petals none. Staminate flowers with 4-7 distinct stamens, the anthers 2-celled; sometimes with a rudimentary pistil. Pistillate flowers with a 2-4-celled (mostly 3-celled) ovary, with 2 or 1 anatropous ovules in each cavity; styles as many as the ovary-cavities, simple. Fruit a capsule or drupe, its carpels 1-2-seeded. Embryo straight; endosperm fleshy, or almost wanting.
About 6 genera and 35 species, only the following and the Californian Simmondsia in continental North America.