Gnetophyta
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]
| Gnetophyta | |
|---|---|
| |
| Welwitschia mirabilis | |
| Scientific classification | |
| Kingdom: | |
| Division: | Gnetophyta
|
| Class: | Gnetopsida
|
| Families & genera | |
|
see text | |
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]
Gnetophyta Media
Welwitschia mirabilis bearing male cones
Ephedra distachya (male cones)
Ephedra distachya (female plant in bloom)
Gnetum gnemon male strobili
Gnetum gnemon female strobilus
Female Ephedra californica cone
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References
- ↑ Peter R. Crane, Patrick Herendeen and Else Marie Friis. Fossils and plant phylogeny. American Journal of Botany 91 (10) (2004). p. 1683–1699. doi:10.3732/ajb.91.10.1683. Retrieved 2011-05-19.
- ↑ Bowe L.M; Coat G. and dePamphilis C.W.. 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 (8) (2000). p. 4092–4097. doi:10.1073/pnas.97.8.4092.
- ↑ Gugerli F.. The evolutionary split of Pinaceae from other conifers: evidence from an intron loss and a multigene phylogeny. Molecular Phylogeny and Evolution 21 (2) (2001). p. 167–175. doi:10.1006/mpev.2001.1004.[dead link]
- ↑ Rai H.S.. Inference of higher-order conifer relationships from a multi-locus plastid data set. Botany 86 (2008). p. 658–669. doi:10.1139/B08-062. Retrieved 2011-05-19.
- ↑ Ickert-Bond S.M; C. Rydin and S.S. Renner. 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. Journal of Systematics and Evolution 47 (5) (2009). p. 444–456. doi:10.1111/j.1759-6831.2009.00053.x.