Gnetum is a genus of , the sole genus in the family Gnetaceae within the Gnetophyta. They are tropical evergreen , and . Unlike other gymnosperms, they possess vessel elements in the xylem. Some species have been proposed to have been the first plants to be insect-pollination as their fossils occur in association with extinct pollinating scorpionflies.
Their leaves are rich in phytochemicals such as Flavonoid and Stilbenoid. Of the species studied so far, Gnetum have photosynthetic and transpiration capacities which are considerably lower than those of other seed plants, due to the absence of multiple chloroplast genes essential for photosynthesis, a trait they seem to share with the other living members of Gnetophyta, Ephedra and Welwitschia, as well as .
Species
There are around 50 different species of
Gnetum. The Catalogue of Life lists 44 species.
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Gnetum interruptum Biye
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Gnetum latispicum Biye
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Gnetum sect. Gnetum
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Gnetum subsect. Gnetum – 2 species of trees; Southeast Asia, Pacific Islands
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Gnetum gnemon – Tibet, Yunnan, Assam, Indochina, Nicobar Islands, Malaysia, Indonesia, Philippines, New Guinea, Melanesia, Micronesia
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Gnetum costatum – New Guinea, Solomon Islands
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Gnetum subsect. Micrognemones – 2 species of lianas; tropical west Africa
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Gnetum subsect. Araeognemones – 9 species of lianas; tropical South America and Central America - Ituá
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Gnetum camporum – Venezuela
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Gnetum leyboldii – Costa Rica, Panama, Venezuela, Colombia, Ecuador, Peru, Amazonian Brazil
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Gnetum nodiflorum – Guianas, Venezuela, Colombia, Ecuador, Peru, northwestern Brazil
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Gnetum paniculatum – Guianas, Venezuela, northwestern Brazil
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Gnetum schwackeanum – Amazonas State of southern Venezuela, northwestern Brazil
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Gnetum urens – Guianas, Venezuela, Peru, northwestern Brazil
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Gnetum venosum – Bolívar State of southern Venezuela, northwestern Brazil
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Gnetum sect. Scandentia Gnetum - about 20 species of lianas; southern Asia
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Gnetum subsect. Stipitati
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Gnetum subsect. Sessiles
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Gnetum acutum – Sarawak
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Gnetum bosavicum – Papua New Guinea
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Gnetum catasphaericum – southern China
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Gnetum chinense Yang, Liu, & Chang – northern China
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Gnetum cleistostachyum – southern China
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Gnetum cuspidatum – Indochina, Indonesia, Malaysia, Philippines
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Gnetum diminutum – Borneo
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Gnetum formosum – Vietnam
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Gnetum giganteum – Guangxi in China
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Gnetum globosum – Pahang in Malaysia
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Gnetum gnemonoides – New Guinea, Bismarck Archipelago, Indonesia, Philippines
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Gnetum hainanense – southern China
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Gnetum klossii – Sabah
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Gnetum leptostachyum – Laos, Thailand, Vietnam, Borneo
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Gnetum loerzingii – Sumatra
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Gnetum luofuense – Fujian, Guangdong, Jiangxi
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Gnetum macrostachyum – Indochina, Indonesia, Malaysia, New Guinea
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Gnetum microcarpum – Myanmar, Thailand, Malaysia, Borneo, Sumatra
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Gnetum neglectum – Borneo
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Gnetum oxycarpum – Sumatra
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Gnetum parvifolium – Laos, Vietnam, southern China
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Gnetum raya – Borneo
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Gnetum ridleyi – Peninsular Malaysia
Uses
Many
Gnetum species are edible, with the
being roasted, and the foliage used as a
leaf vegetable.
[Hoe, V.B. and Siong, K.H., "The Nutritional Value of Indigenous Fruits and Vegetables in Sarawak,"Asia-Pacific Journal of Clinical Nutrition, Vol. 8, no. 1, 1998, pp 24-31] The plant is harvested and yields a useful fiber. There is no sense of danger in consuming the fruit or the seeds.
There is also a study done on the plant to see if it has any medicinal properties, finding some anti-coagulation effects due to its stilbenoid content. The family Gnetaceae is well known as a rich source of plant-derived as well as Cyperaceae, Dipterocarpaceae, Fabaceae, and Vitaceae.
Conservation
Some species of
Gnetum are in danger of dying out. The habitats are being removed with the trees being cut down to create industry. The tropical rainforest are being destroyed so many of the species are going extinct such as
Gnetum oxycarpum. The rainforests are being torn down and being turned into farmland.
Gnetum live in only a small part of the rainforest.
== Gallery ==
carpellate/female cones]]
]]
'' seeds]]
External links
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Gymnosperm Database - Gnetum
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Sorting Gnetum names
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Uses of Gnetum in Africa (FAO)
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Kloypan, Chiraphat & Jeenapongsa, Rattima & Sri-In, Piyawit & Chanta, Surin & Dokpuang, Dech & Tip-Pyang, Santi & Surapinit, Serm. (2012). Stilbenoids from Gnetum macrostachyum Attenuate Human Platelet Aggregation and Adhesion. Phytotherapy research : PTR. 26. 1564–8. 10.1002/ptr.4605.
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http://www.theplantlist.org/tpl1.1/record/kew-334161...
