?Psilotales
Closeup of Psilotum nudum
Scientific classification
Kingdom: Plantae Division: Pteridophyta Class: Ophioglossopsida Order: Psilotales
Families
Psilotaceae Tmesipteridaceae Zosterophyllopsida† Image of Psilotum nudum made by Eric Guinther in Hawaii (near Kaneohe) in DEcember 2003 and released under the GNU Free Documentation License. ... Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ... Divisions Green algae Chlorophyta Charophyta Land plants (embryophytes) Non-vascular plants (bryophytes) Marchantiophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) †Rhyniophyta - rhyniophytes †Zosterophyllophyta - zosterophylls Lycopodiophyta - clubmosses †Trimerophytophyta - trimerophytes Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta... Classes Marattiopsida Osmundopsida Gleicheniopsida Pteridopsida A fern, or pteridophyte, is any one of a group of some twenty thousand species of plants classified in the Division Pteridophyta, formerly known as Filicophyta. ... Families and Genera Family Ophioglossaceae Ophioglossum Cheiroglossa Family Botrychiaceae Botrychium Botrypus Sceptridium Family Helminthostachiaceae Helminthostachys zeylanica The Ophioglossophyta (lit. ... Species Psilotum nudum (L.) Beauvois Psilotum complanatum Sw. ...

Psilotales (the "whisk ferns") is an order (i.e., order) of the Class Ophioglossopsida. This order contains only two living genera, Psilotum, a small shrubby plant of the dry tropics, and Tmesipteris, an epiphyte found in Australia, New Zealand, and New Caledonia. There has long been controversy about the relationships of the Psilotophyta, with some claiming that they are ferns (Pteridophyta), and others maintaining that they are descendants of the first vascular plants (the Psilophyta of the Devonian period). Recent evidence from DNA demonstrates a much closer relationship to the ferns, and that they are closely related to the Ophioglossales, in particular. Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... Families and Genera Family Ophioglossaceae Ophioglossum Cheiroglossa Family Botrychiaceae Botrychium Botrypus Sceptridium Family Helminthostachiaceae Helminthostachys zeylanica The Ophioglossophyta (lit. ... Species Psilotum nudum (L.) Beauvois Psilotum complanatum Sw. ... An example of an epiphyte assemblage of orchids and bromeliads in a garden setting The term epiphyte refers to any plant that grows upon or attached to another living plant. ... Classes Marattiopsida Osmundopsida Gleicheniopsida Pteridopsida 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. ... Psilophyta is a division of the Kingdom Plantae. ... Disambiguation: Devonian is sometimes used to refer to the Southwestern Brythonic language, and the people of the county of Devon are sometimes referred to as Devonians The Devonian is a geologic period of the Paleozoic era. ... The general structure of a section of DNA Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the biological development of a cellular form of life or a virus. ... Families and Genera Family Ophioglossaceae Ophioglossum Cheiroglossa Family Botrychiaceae Botrychium Botrypus Sceptridium Family Helminthostachiaceae Helminthostachys zeylanica The Ophioglossophyta (lit. ...

All Psilotales share a few characteristics. Psilotales are vascular plants. They lack leaves, instead having small outgrowths called enations. The enations are not considered true leaves because there is only a vascular bundle just underneath them, but not inside, as in leaves. Psilotales also do not have true roots. They are anchored by rhizoids. Absorption is aided by symbiotic fungi called mycorrhizae. Divisions Non-seed-bearing plants Equisetophyta Lycopodiophyta Psilotophyta Pteridophyta Superdivision Spermatophyta Pinophyta Cycadophyta Ginkgophyta Gnetophyta Magnoliophyta The vascular plants are plants in the Kingdom Plantae (also called Viridiplantae) that have specialized tissues for conducting water. ... ROOT is an object-oriented software package developed by CERN. It was originally designed for particle physics data analysis and contains several features specific to this field, but it is also commonly used in other applications such as astronomy and data mining. ... Rhizoids, in fungi, are small branching hyphae that grow downwards from the stolons that anchor the fungus. ... Divisions Chytridiomycota Zygomycota Glomeromycota Ascomycota Basidiomycota Deuteromycota A fungus (plural fungi) is a eukaryotic organism that digests its food externally and absorbs the nutrient molecules into its cells. ... A mycorrhiza (typically seen in the plural form mycorrhizae meaning fungus roots) is a distinct type of root symbiosis in which individual hyphae extending from the mycelium of a fungus colonize the roots of a host plant. ...

Three sporangia are united into a synangium, which is considered to be a very reduced series of branches. There is a thick tapetum to nourish the developing spores, as is typical of eusporangiate plants. The gametophyte looks like a small piece of subterranean stem, but produces antheridia and archegonia. A sporangium (pl. ... Spores produced in a sporic life cycle. ... // Overview A gametophyte is the haploidor possibly diploid structure or phase of life of a sexually-reproducing plant. ... Diagram of antheridium anatomy An antheridium (plural: antheridia) is a structure or organ of the gametophyte phase of certain plants producing and containing the spermatids or male gametes. ... An archegonium (pl: archegonia) (from the Greek arche = beginning and gonos = born) is a multicellular structure or organ of the gametophyte phase of certain plants producing and containing the ovum or female gamete. ...

External links

• Introduction to the Psilotales