Lycopod

The Lycopods (Lycopodiophyta or Lycophyta) are the oldest surviving vascular plant division. This is a subdivision of the plant kingdom. Its earliest fossils are from 428–410 million years ago.p99

The Lycopods include some of the most primitive (basal) living species. They reproduce by shedding spores and have macroscopic alternation of generations.'macroscopic' = can be seen with the naked eye, e.g. instead of requiring a microscope Members of Lycopodiophyta have a protostele,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. and the sporophyte generation is dominant.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.

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.

 The first coalfields 
The lycopods, or club mosses, are the main plants in the Carboniferous rain forests. They were only partly eaten by insects and other life-forms. Mostly they formed swamplands which in the course of time became coal measures. In fact most of the coal from the Carboniferous period comes from these swamplands.Gensel P.G. & Edwards D. (eds). Plants invade the land : evolutionary & environmental perspectives. New York: Columbia University Press. ISBN 978-0-231-11161-4

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

Lycopodiales: Clubmosses
Isoetales: Quillworts
Selaginellales: Spikemosses

 References 

Category:Vascular plants