| Gnetum | |
|---|---|
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| Gnetum macrostachyum in Thailand | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Division: | Gnetophyta |
| Class: | Gnetopsida |
| Order: | Gnetales T.M.Fries |
| Family: | Gnetaceae Lindleyx |
| Genus: | Gnetum L. |
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| Distribution | |
| Synonyms[1] | |
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Gnetum is the onlygenus in the plant familyGnetaceae. They aregymnosperms: their seeds are naked, whereas the seeds of flowering plants are covered.[2]
Plants inGnetum areevergreen. Most of them are woody vines, but some are big enough to be trees. They grow in warmer, tropical regions of the world.[2] There are over 50 species living. Although some are endangered, the group as a whole are not threatened. Some species are in danger of dying out because they only live in small areas, and the forest where they grow is being turned into land for farming.[3]
Gnetum may have been one of the first plants to bepollinated by insects, with other members of this group such asEphedra andWelwitschia.[2]
Gnetophyte fossils have been found that date from thePermian[4] and theTriassic. Fossils dating back to theJurassic have been found, though whether or not they belong to the gnetophytes is uncertain.[5] Overall, the fossil record is richest in the earlyCretaceous: fossils of plants,seeds, andpollen have been found which are clearly gnetophytes.[5]