Gourt > Science > Biology > Flora and Fauna > Plantae > Polypodiophyta (144)
A fern is any one of a group of about 20,000 species of plants classified in the phylum or division Pteridophyta, also known as Filicophyta. The group is also referred to as polypodiophyta, or polypodiopsida when treated as a subdivision of tracheophyta (vascular plants). The study of ferns is called pteridology. The term pteridophytes has traditionally been used to describe all seedless vascular plants so is synonymous with "ferns and fern allies". This can be confusing given that the fern phylum Pteridophyta is also sometimes referred to as pteridophytes.
A fern is a vascular plant that differs from the more primitive lycophytes in having true leaves (megaphylls), and from the more advanced seed plants (gymnosperms and angiosperms) in lacking seeds. Like all vascular plants, it has a life cycle, often referred to as alternation of generations, characterised by a diploid sporophytic and a haploid gametophytic phase. Unlike the gymnosperms and angiosperms, in ferns the gametophyte is a free-living organism. The life cycle of a typical fern is as follows:
- A sporophyte (diploid) phase produces haploid spores by meiosis;
- A spore grows by cell division into a gametophyte, which typically consists of a photosynthetic prothallus
- The gametophyte produces gametes (often both sperm and eggs on the same prothallus) by mitosis
- A mobile, flagellate sperm fertilizes an egg that remains attached to the prothallus
- The fertilized egg is now a diploid zygote and grows by mitosis into a sporophyte (the typical "fern" plant).
Ferns :: Plants
Pteridophyta :: Plantae
American Fern Society - Information on the biology and cultivation of ferns; activities of the society including a spore exchange and publication of Fiddlehead Forum, American Fern Journal, and Pteridologia.
Meta Description: [ The American Fern Society ]
British Fern Species - Searchable database.
Meta Description: [ ferns database ]
Ferns Around Washington, DC - A collection of images and information on ferns growing in the DC area.
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Ferns et al of New England and Bermuda - Lists all native pteridophyte species and some hybrids, with photographs of most and data pages for some.
Ferns of Barbados - Checklist plus distribution data and links for each species.
Ferns of Fern Forest and South Florida - Photographs and descriptions of the ferns of southern Florida.
Ferns of Great Britain and Ireland - Small images of 39 antique prints by Thomas Moore, 1855.
Meta Description: [ Rare-Prints.com specializes in 19th century antique prints and 20th century investment quality reproductions. ]
Ferns of the Canberra Region - A site about ferns in southeastern Australia, their ecology, how to grow them, information on ferns in general, with numerous photographs.
Meta Description: [ A website about the wild ferns that grow in this part of southeastern Australia, the conditions they need and their ecology, with many photographs and detailed descriptions. ]
Filicopsida - Introduction to ferns from the Tree of Life project.
Gallery of Connecticut Ferns - Photos and brief information indexed by common and scientific names.
Meta Description: [ Ferns of Connecticut -- indexed by
by common name and by scientific name. From the Connecticut Botanical Society. ]
Introduction to the Ferns - The ferns are an ancient lineage of plants, dating back to at least the Devonian. They include three living groups - Marattiales, Ophioglossales, and leptosporangiate ferns - as well as a couple of extinct groups.
Leptosporangiate Ferns - Next to the flowering plants, the leptosporangiate ferns are the most diverse group of living land plants. Estimates place their diversity at about 12,000 species in around 300 genera. This page is part of the tree of life phylogeny project.
Phylogeny and evolution of ferns (Monilophytes) - Scientific paper from American Journal of Botany 2004 showing that Psilotophyta and Equisetophya are in the Monilophyte clade with the other ferns.
Phylum Pterophyta - Includes a description of the fern life cycle, list of families and genera, and links to images of selected representatives.
Pterophyta - Introduction to the systematics of the ferns, with family descriptions and images.
Pterophyta Taxa - List of all families and genera, with numbers of species and ranges.
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Recent pteridophyte name changes - Refers to Australian taxa and mainly changes effected in the 1990s.
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