Gnetophyta

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Gnetophyta
Welwitschia at Ugab River basin.jpg
Welwitschia mirabilis
Scientific classification
Kingdom:
Division:
Class:
Families & genera

see text

The Gnetophytes are a group of seed plants with three genera. Their evolutionary relationships are unclear, but it is now clear that they are related to each other.[1]

The three genera are:

By looking at the structure of these organisms (morphology) and the DNA (molecular taxonomy), scientists have found that Gnetum and Welwitschia are more closely related to each other than to Ephedra.[2][3][4][5]

References[change | change source]

  1. Peter R. Crane, Patrick Herendeen and Else Marie Friis (2004). "Fossils and plant phylogeny". American Journal of Botany. 91: 1683–1699. doi:10.3732/ajb.91.10.1683.
  2. Bowe L.M; Coat G. and dePamphilis C.W. (2000). "Phylogeny of seed plants based on all three genomic compartments: extant gymnosperms are monophyletic and Gnetales' closest relatives are conifers". Proceedings of the National Academy of Science. 97: 4092–4097. doi:10.1073/pnas.97.8.4092.
  3. Gugerli F.; et al. (2001). "The evolutionary split of Pinaceae from other conifers: evidence from an intron loss and a multigene phylogeny". Molecular Phylogeny and Evolution. 21 (2): 167–175. doi:10.1006/mpev.2001.1004. PMID 11697913.
  4. Rai H.S.; et al. (2008). "Inference of higher-order conifer relationships from a multi-locus plastid data set". Botany. 86: 658–669. doi:10.1139/B08-062.
  5. Ickert-Bond S.M; C. Rydin and S.S. Renner (2009). "A fossil-calibrated relaxed clock for Ephedra indicates an Oligocene age for the divergence of Asian and New World clades, and Miocene dispersal into South America" (PDF). Journal of Systematics and Evolution. 47: 444–456.