**Description and Characteristics:**
– Lycophytes reproduce via spores and exhibit alternation of generations.
– They are characterized by lateral sporangia and exarch protosteles.
– Extinct zosterophylls had enations, while extant lycophytes have microphylls.
– Lycophytes were predominant during the Carboniferous period.
– Some species like Lepidodendrales were tree-like, growing over 40 meters tall.
**Taxonomy and Classification:**
– Extant lycophytes are classified under the class Lycopodiopsida according to the PPGI classification.
– There are approximately 1,290 to 1,340 species of lycophytes.
– Terms like Lycopodiophyta and Lycophyta can be ambiguous.
– English names like lycophyte may lack clarity in inclusivity.
– For further details on classification, refer to Lycopodiopsida §Classification.
**Phylogeny and Evolution:**
– A significant cladistic analysis was conducted by Kenrick and Crane in 1997.
– Crane et al. in 2004 presented simplified cladograms for lycophytes.
– There are differing views on the placement of zosterophylls in relation to lycophytes.
– Extinct orders of lycophytes display varying relationships in cladograms.
– Genera like Asteroxylon and Leclercqia represent stages in microphyll evolution.
**Gallery and Fossil Evidence:**
– Fossils such as Lycopodites and Lepidodendron provide insights into ancient lycophytes.
– Modern lycophyte orders include Lycopodiales and Isoetales.
– Restorations of extinct genera like Pleuromeia offer glimpses into ancient lycophytes.
– Fossilized lycopsids and reconstructions of Silurian plants showcase lycophyte diversity.
– Fossil evidence like lycopod bark and stigmarian roots aid in understanding lycophyte evolution.
**Research Studies and Publications:**
– Various publications by authors like Kenrick and Crane offer detailed studies on lycophytes.
– Studies on the earliest club mosses have been conducted in regions like Victoria, Australia.
– Books on plant evolution and biology provide valuable insights into lycophytes.
– Taxonomic proposals, conservation efforts, and paleobotanical research contribute to lycophyte knowledge.
– Academic resources such as ‘Biology of Plants’ and ‘Paleobotany’ delve into lycophyte biology and evolution.
The lycophytes, when broadly circumscribed, are a group of vascular plants that include the clubmosses. They are sometimes placed in a division Lycopodiophyta or Lycophyta or in a subdivision Lycopodiophytina. They are one of the oldest lineages of extant (living) vascular plants; the group contains extinct plants that have been dated from the Silurian (ca. 425 million years ago). Lycophytes were some of the dominating plant species of the Carboniferous period, and included the tree-like Lepidodendrales, some of which grew over 40 metres (130 ft) in height, although extant lycophytes are relatively small plants.
| Lycophyte Temporal range: Silurian to recent
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|---|---|
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| Collage of modern lycophytes. Upper left: Lycopodium clavatum (Lycopodiales, Lycopodioideae) Lower left: Huperzia serrata (Lycopodiales, Huperzioideae) Top right: Isoetes japonica (Isoetales) Right centre: Selaginella tamariscina Lower right: Selaginella remotifolia Selaginellales | |
Scientific classification 
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| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Lycophytes |
| Classes | |
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The scientific names and the informal English names used for this group of plants are ambiguous. For example, "Lycopodiophyta" and the shorter "Lycophyta" as well as the informal "lycophyte" may be used to include the extinct zosterophylls or to exclude them.