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.
This is a small order or, as considered by some, a tribe, of the Coniferae. The species are shrubs or trees with jointed branchlets and simple net-veined broad or small scale-like leaves. The fruit is a small 2-seeded berry in the only genus concerning us. There are only three genera referred here. Gnetum has large opposite leaves, and Welwitschia is remarkable for its short thick tabular flat-topped trunk with two opposite leaves.