a family of tropical gymnosperms in the order Gnetales (division Gnetophyta), composed of one genus, Gnetum, with 30 or more species. Trees predominate among the African species; most of the Asian varieties are woody vines, but among the exceptions is G. gnemon, a tree about 20 metres (65 feet) tall that yields a useful fibre and an edible, plumlike fruit. Other species occur in the Neotropics. The conspicuous, netlike veining of the broad leaves of Gnetum species superficially resembles that of angiosperms. The ovules (potential seeds) are enclosed, and conducting cells in the wood include open-ended pipes known as vessels; the latter condition is also characteristic of angiosperms.