the only genus of the family Ephedraceae (division Gnetophyta), an evolutionally isolated group of low, straggling, or climbing gymnospermous desert shrubs and the only family in the order Gnetales of the division Gnetophyta. Ephedra contains 65 species, among them the Asiatic plants known as ma huang, sources of the decongestant drug ephedrine. The joint pine of the eastern Mediterranean region is Ephedra fragilis. The North American species include the plants joint fir and Mormon tea bush, sources of food and medicinals. The leaves, reduced to scales about one centimetre long, are opposite or whorled about the nodes of green branchlets that resemble those of the horsetail. In certain anatomical and reproductive features, the plants are close to the angiosperms. A species of Ephedra grows in Kashmir at about 5,300 metres (nearly 17,400 feet), the highest altitude at which vascular plants are known to occur.