Gnetum

Gnetum
Gnetum macrostachyum in Thailand
Scientific classification
Kingdom: Plantae
Division: Gnetophyta
Class: Gnetopsida
Order: Gnetales
T.M. Fries
Family: Gnetaceae
Lindley
Genus: Gnetum
L.
Map showing the range of Gnetum
Distribution
Synonyms[1]

Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms they possess vessel elements in the xylem. Some species have been proposed to have been the first plants to be insect pollinated as their fossils occur in association with the extinct pollinating scorpionflies.[2] Molecular phylogenies based on nuclear and plastid sequences from most of the species indicate hybridization among some of the Southeast Asian species. Fossil-calibrated molecular-clocks suggest that the Gnetum lineages now found in Africa, South America, and Southeast Asia are the result of ancient long-distance dispersal across seawater.[3] [4]

Species

Uses

Many Gnetum species are edible, with the seeds being roasted, and the foliage used as a leaf vegetable. Some are also valued in herbal medicine.

References

  1. Kew World Checklist of Selected Plant Families
  2. Ren D, Labandeira CC, Santiago-Blay JA, Rasnitsyn A, Shih CK, Bashkuev A, Logan MA, Hotton CL, Dilcher D. (2009). Probable Pollination Mode Before Angiosperms: Eurasian, Long-Proboscid Scorpionflies. Science, 326 (5954), 840-847. doi:10.1126/science.1178338
  3. Won H, Renner SS: The internal transcribed spacer of nuclear ribosomal DNA in the gymnosperm Gnetum. Molecular Phylogenetics and Evolution 2005, 36:581-597. doi:10.1016/j.ympev.2005.03.011
  4. Won, H., and S. S. Renner. 2006. Dating dispersal and radiation in the gymnosperm Gnetum (Gnetales) – clock calibration when outgroup relationships are uncertain. Systematic Biology 55(4): 610-622. doi:10.1080/10635150600812619

External links

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