The class Ginkgoopsida contains the contains the ginkgo, Ginkgo biloba, the last surviving species of a once large and flourishing group of gymnosperms. The class Gnetopsida contains three genera in separate orders, all of great botanical and evolutionary interest. Gnetum is a tropical tree or shrub with broad leaves much like those of an angiosperm. Ephedra is a low shrub with scalelike leaves that grows in arid regions of western North America and in China; from it is produced the traditional Chinese herbal medicine ma huang and the drug ephedrine. Welwitschia, a desert plant of SW Africa, typically has only two large, leathery leaves that persist for the life of the plant, which can be as long as 1,500 years.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.