A gametophyte is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the sexual phase in the life cycle of plants and algae. It develops sex organs that produce gametes, haploid sex cells that participate in fertilization to form a diploid zygote which has a double set of chromosomes. Cell division of the zygote results in a new diploid multicellular organism, the second stage in the life cycle known as the sporophyte. The sporophyte can produce haploid spores by meiosis that on germination produce a new generation of gametophytes.
A sporangium ; pl.: sporangia) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life cycle. Sporangia can produce spores by mitosis, but in nearly all land plants and many fungi, sporangia are the site of meiosis and produce genetically distinct haploid spores.
Alternation of generations is the predominant type of life cycle in plants and algae. In plants both phases are multicellular: the haploid sexual phase – the gametophyte – alternates with a diploid asexual phase – the sporophyte.
Isoetes, commonly known as the quillworts, is a genus of lycopod. It is the only living genus in the family Isoetaceae and order Isoetales. There are currently 192 recognized species, with a cosmopolitan distribution mostly in aquatic habitats but with the individual species often scarce to rare. Some botanists split the genus, separating two South American species into the genus Stylites, although molecular data place these species among other species of Isoetes, so that Stylites does not warrant taxonomic recognition. Species virtually identical to modern quillworts have existed since the Jurassic epoch, though the timing of the origin of modern Isoetes is subject to considerable uncertainty.
The order Salviniales is an order of ferns in the class Polypodiopsida.
Gleicheniales is an order of ferns in the subclass Polypodiidae. The Gleicheniales have records potentially as early as the Carboniferous, but the oldest unambiguous records date to the Permian.
Pellaea is a genus of ferns in the Cheilanthoideae subfamily of the Pteridaceae. The genus name is derived from the Greek word πελλος (pellos), meaning "dark," and refers to the brown stems. Many members of the genus are commonly known as cliffbrakes. They primarily grow in rocky habitats, including moist rocky canyons, slopes, and bluffs.
Pteridaceae is a family of ferns in the order Polypodiales, including some 1150 known species in ca 45 genera, divided over five subfamilies. The family includes four groups of genera that are sometimes recognized as separate families: the adiantoid, cheilanthoid, pteridoid, and hemionitidoid ferns. Relationships among these groups remain unclear, and although some recent genetic analyses of the Pteridales suggest that neither the family Pteridaceae nor the major groups within it are all monophyletic, as yet these analyses are insufficiently comprehensive and robust to provide good support for a revision of the order at the family level.
Linnaea is a plant genus in the honeysuckle family Caprifoliaceae. Until 2013, the genus included a single species, Linnaea borealis. In 2013, on the basis of molecular phylogenetic evidence, the genus was expanded to include species formerly placed in Abelia, Diabelia, Dipelta, Kolkwitzia and Vesalea. However, this is rejected by the majority of subsequent scientific literature and flora.
Thelypteris is a genus of ferns in the subfamily Thelypteridoideae, family Thelypteridaceae, order Polypodiales. Two radically different circumscriptions of the genus are in use as of January 2020. In the Pteridophyte Phylogeny Group classification of 2016, the genus is a very small one with about two species. In other approaches, the genus is the only one in the subfamily Thelypteridoideae, and so includes between 875 and 1083 species.
Heterospory is the production of spores of two different sizes and sexes by the sporophytes of land plants. The smaller of these, the microspore, is male and the larger megaspore is female. Heterospory evolved during the Devonian period from isospory independently in several plant groups: the clubmosses, the ferns including the arborescent horsetails, and progymnosperms. This occurred as part of the process of evolution of the timing of sex differentiation.
Doodia media, also known as rasp fern, is a fern species in the family Blechnaceae. The species was formally described by botanist Robert Brown in 1810. Distribution of the species includes New Zealand's North Island and the upper part of the South Island. It is also found in Australia and Lord Howe Island.
Jamesonia is a genus of ferns in the subfamily Pteridoideae of the family Pteridaceae. It now includes the formerly separate genus Eriosorus.
Pteris semipinnata is a fern species in the Pteridoideae subfamily of the Pteridaceae. It is mainly distributed in tropical regions, such as southern China, the Philippines, Vietnam, Laos, Thailand, Myanmar, Malaysia, Sri Lanka and northern India. It is also found in Japan and Bhutan. Pteris semipinnata grows in open forests, on the acid soil near streams or rocks, below 900 meters above sea level. It is native to Hong Kong and Taiwan. It should also be native to China. In any case, Hong Kong is currently a city in China, so it can be said that Pteris semipinnata is native to China.
Pteris tremula, commonly known as Australian brake, tender brake, tender brakefern, shaking brake is a fern species of the family Pteridaceae native to sheltered areas and forests in eastern Australia and New Zealand. It has pale green, lacy fronds of up to 2 meters in length, with an erect, tufted rhizome that is covered with narrow brown scales. It is fast-growing and easy to grow in cultivation, but can become weedy.
Gleichenia microphylla is a small fern growing in Australia and New Zealand.
Pteris lydgatei is a rare fern species in the Pteridoideae subfamily of the Pteridaceae. It is known by the common name Lydgate's brake and is endemic to Hawaii, where it is known from the islands of Oʻahu, Molokaʻi, and Maui. It was once thought to be extinct until it was rediscovered in the 1990s. There are fewer than 40 individuals in the wild. This is a federally listed endangered species of the United States.
Dr Maarten Joost Maria Christenhusz is a Dutch botanist, natural historian and photographer.
Argyrochosma nivea is an Andean fern species in the genus Argyrochosma.
Hemionitis is a genus of ferns in the subfamily Cheilanthoideae of the family Pteridaceae. Its circumscription varies greatly in different systems of fern classification. In the Pteridophyte Phylogeny Group classification of 2016, it was one of more than 20 genera in the subfamily Cheilanthoideae, and was said to have five species. Other sources treat it as the only genus in the subfamily, and so accept about 450 species. With the restricted circumscription, species are native to tropical America.
