Lycopod

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Lycopod
Temporal range: Silurian to Recent
Lycopodiella inundata
Scientific classification
Kingdom: Plantae
Division: Lycopodiophyta
Cronquist, Takht. & W.Zimm.[1][2]

The Lycopods (Lycopodiophyta or Lycophyta) is the oldest surviving vascular plant division. It is a vascular plant subdivision of the plant kingdom. Its earliest fossils are from 428–410 million years ago.[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.[5] Members of Lycopodiophyta have a protostele,[6] and the sporophyte generation is dominant.[7][8]

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 | change source]

There are around 1,200 living species of Lycopodiophyta; they are generally divided into three orders.[9] There are also some extinct groups. There are different opinions as to how the whole group should be classified.[10][11]p8 Living groups are:

References[change | change source]

  1. Cronquist A; Takhtajan A. & Zimmermann W. 1966 On the higher taxa of Embryobionta. Taxon 15 (15): 129–134. doi:10.2307/1217531 .
  2. Cantino, Philip D. et al 2007. "Towards a phylogenetic nomenclature of Tracheophyta". Taxon 56 (3): E1–E44.
  3. 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 .
  4. McElwain, Jenny C; et al. (2002). The evolution of plants. Oxford: Oxford University Press. ISBN 0-19-850065-3 .
  5. 'macroscopic' = can be seen with the naked eye, e.g. instead of requiring a microscope
  6. 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.
  7. The sporophyte generation is diploid, and produces the spores. The spores produce the haploid gametophyte generation.
  8. Eichhorn, Evert, and Raven 2005. Biology of plants, 7th ed. 381-388.
  9. 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 .
  10. Yatsentyuk S.P. et al 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 .
  11. "www.ncbi.nlm.nih.gov". http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Undef&id=3243. Retrieved 2009-03-19.