Lycopodiophyta
| Lycopodiophyta Temporal range: Silurian to Recent |
|
|---|---|
 |
|
| Lycopodiella inundata | |
| Scientific classification | |
| Kingdom: | Plantae |
| Division: | Lycopodiophyta Cronquist, Takht. & W.Zimm.[1] [P.D. Cantino & M.J. Donoghue][2] |
The Division Lycopodiophyta (sometimes called Lycophyta or Lycopods) is a tracheophyte subdivision of the plant kingdom. It is the oldest surviving vascular plant division. Earliest fossils dated from 428–410 million years old.[3][4]p99
The Lycopods include some of the most primitive (basal) living species. They reproduce by shedding spores and have macroscopic alternation of generations. Members of Lycopodiophyta have a protostele,[5] and the sporophyte generation is dominant.[6][7]
Lycopods differ from all other vascular plants in having microphylls, leaves that have only a single vein rather than the much more complex megaphylls found in ferns and seed plants.
Classification [change]
There are around 1,200 living species of Lycopodiophyta; they are generally divided into three orders.[8] There are also some extinct groups. There are different opinions as to how the whole group should be classified.[9][10]p8 Living groups are:
References [change]
- ↑ Cronquist, A.; A. Takhtajan, W. Zimmermann (1966). "On the higher taxa of Embryobionta". Taxon (International Association for Plant Taxonomy (IAPT)) 15 (15): 129–134. doi:10.2307/1217531.
- ↑ Cantino, Philip D. et al. (2007). "Towards a phylogenetic nomenclature of Tracheophyta". Taxon 56 (3): E1–E44.
- ↑ Kenrick, Paul; Crane, Peter R. (1997). The origin and early diversification of land plants: a cladistic study. Washington D.C.: Smithsonian Institution Press. pp. 339–340. ISBN 1-56098-730-8.
- ↑ McElwain, Jenny C; et al. (2002). The evolution of plants. Oxford: Oxford University Press. ISBN 0-19-850065-3.
- ↑ A central core of vascular tissue which conducts water and nutrients up, and manufactured substances down. The stele also supports the plant above the ground.
- ↑ The sporophyte generation is diploid, and produces the spores. The spores produce the haploid gametophyte generation.
- ↑ Eichhorn, Evert, and Raven 2005. Biology of plants, 7th ed. 381-388.
- ↑ Callow R.S. & Cook, Laurence Martin (1999). Genetic and evolutionary diversity: the sport of nature. Cheltenham: S. Thornes. p. 8. ISBN 0-7487-4336-7.
- ↑ Yatsentyuk, S.P.; Valiejo-Roman, K.M.; Samigullin, T.H.; Wilkström, N.; & Troitsky, A.V. (2001). "Evolution of Lycopodiaceae inferred from spacer sequencing of chloroplast rRNA genes". Russian Journal of Genetics 37 (9): 1068–73. doi:10.1023/A:1011969716528.
- ↑ "www.ncbi.nlm.nih.gov". http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Undef&id=3243. Retrieved 2009-03-19.
