Gnetum

Gnetum is a genus of evergreen gymnosperm plants in the family Gnetaceae, comprising woody climbers, shrubs, and small trees. It belongs to the order Gnetales, a small and ancient lineage that also includes Welwitschia and Ephedra. Gnetum is native to tropical regions of Africa, Asia, and the Americas, where it occupies rainforest, forest margins, and secondary habitats. The genus contains about 35 species, with Gnetum gnemon (melinjo) and Gnetum africanum among the best known and widely used by humans.

Morphology and ecology: Members are typically evergreen, with large, leathery leaves arranged either alternately or oppositely depending on species. Many species are climbing lianas, while others grow as trees or shrubs. Gnetum species are dioecious, having separate male and female plants. Flowers are inconspicuous, and the conspicuous reproductive structures are the unisexual inflorescences on each plant. The fruit is a fleshy structure containing one or more seeds, produced by female plants.

Taxonomy and phylogeny: Gnetum is one of the three genera in Gnetophyta, sharing some features with angiosperms such as vessel-bearing xylem, which has made its evolutionary position a subject of study and debate. Molecular data place Gnetum in an early-diverging gymnosperm lineage, though its exact relationship to true flowering plants remains debated.

Uses: In Africa, leaves of Gnetum africanum are an important leafy vegetable; in Asia, leaves of several species are consumed in soups and salads. The seeds of some species are edible when processed and used to produce oil or flavoring; fruit and foliage have traditional medicinal uses in various regions.

Conservation: Deforestation and habitat alteration threaten several species, and some are considered vulnerable or endangered.