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.