A sporangium is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. 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.
Schizaeales is an order of ferns.
Equisetales is an order of subclass Equisetidae with only one living family, Equisetaceae, containing the genus Equisetum (horsetails).
The order Cyatheales, which includes the tree ferns, is a taxonomic division of the fern class, Polypodiopsida. No clear morphological features characterize all of the Cyatheales, but DNA sequence data indicate the order is monophyletic. Some species in the Cyatheales have tree-like growth forms, but others have rhizomes.
A pteridophyte is a vascular plant that reproduces using spores. Because pteridophytes produce neither flowers nor seeds, they are also referred to as "cryptogams", meaning that their means of reproduction is hidden. The pteridophytes include the ferns, horsetails, and the lycophytes. These are not a monophyletic group because ferns and horsetails are more closely related to seed plants than to the lycophytes. Therefore, "Pteridophyta" is no longer a widely accepted taxon, although the term pteridophyte remains in common parlance, as do pteridology and pteridologist as a science and its practitioner, to indicate lycophytes and ferns as an informal grouping, such as the International Association of Pteridologists and the Pteridophyte Phylogeny Group.
The zosterophylls were a group of extinct land plants that first appeared in the Silurian period. The taxon was first established by Banks in 1968 as the subdivision Zosterophyllophytina; they have since also been treated as the division Zosterophyllophyta and the class or plesion Zosterophyllopsida. They were among the first vascular plants in the fossil record, and had a world-wide distribution. They were probably stem-group lycophytes, forming a sister group to the ancestors of the living lycophytes. By the late Silurian a diverse assemblage of species existed, examples of which have been found fossilised in what is now Bathurst Island in Arctic Canada.
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, pteroid, 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.
Polyphlebium angustatum is a species of fern in the family Hymenophyllaceae. It is found in South America and on a number of Atlantic islands, including Tristan da Cunha. The genus Polyphlebium is accepted in the Pteridophyte Phylogeny Group classification of 2016 (PPG I), but not by other sources. As of October 2019, Plants of the World Online sank the genus into a broadly defined Trichomanes, treating this species as Trichomanes angustatum.
Didymoglossum melanopus is a species of fern in the family Hymenophyllaceae. It is endemic to Ecuador.
Cystopteris is a genus of ferns in the family Cystopteridaceae. These are known generally as bladderferns or fragile ferns. They are found in temperate areas worldwide. This is a very diverse genus and within a species individuals can look quite different, especially in harsh environments where they experience stress and remain small and stunted. Also, they hybridize easily with each other. Identifying an individual can be challenging. In general these are rhizomatous perennials which may grow in rocky areas or in soil. Their leaves are multiply pinnate, in that each leaflet is divided into smaller parts. The sori are usually rounded and are covered in an inflated bladder-like indusium.
Hicklingia is a genus of extinct plants of the Middle Devonian. Compressed specimens were first described in 1923 from the Old Red Sandstone of Scotland. Initially the genus was placed in the "rhyniophytes", but this group is defined as having terminal sporangia, and later work showed that the sporangia of Hicklingia were lateral rather than strictly terminal, so that it is now regarded as having affinities with the zosterophylls.
Polypodiineae is a suborder of ferns in the order Polypodiales. It is equivalent to the clade eupolypods I in earlier systems, and to the very broadly defined family Polypodiaceae in the classification of Christenhusz & Chase (2014). It probably diverged from the suborder Aspleniineae during the mid-Cretaceous. The divergence is supported by both molecular data and an often overlooked morphological characteristic which lies in the vasculature of the petiole. Most species that make up the suborder have three vascular bundles. The only exceptions are the grammitid ferns which have one, and the genus Hypodematium which has two. This differs from eupolypods II which mostly have two vascular bundles.
Plenasium vachellii is a fern in the family Osmundaceae. The genus Plenasium is recognized in the Pteridophyte Phylogeny Group classification of 2016 (PPG I); however, some sources place all Plenasium species in a more broadly defined Osmunda, treating this species as Osmunda vachellii. It is native to south-central and southeast China and Indochina.
Plenasium angustifolium is a fern in the family Osmundaceae. The genus Plenasium is recognized in the Pteridophyte Phylogeny Group classification of 2016 (PPG I); however, some sources place all Plenasium species in a more broadly defined Osmunda, treating this species as Osmunda angustifolia. It is native to eastern Thailand, Laos and southern China, and has been introduced into India and Sri Lanka.
Plenasium banksiifolium is a fern in the family Osmundaceae. The genus Plenasium is recognized in the Pteridophyte Phylogeny Group classification of 2016 (PPG I); however, some sources place all Plenasium species in a more broadly defined Osmunda, treating this species as Osmunda banksiifolia. It is native along the Pacific coast of Asia, being found in the Kamchatka Peninsula, the Ryukyu Islands, Japan, southeast China, Taiwan, the Philippines, Borneo, Sulawesi and Java.
Cephalomanes is a fern genus in the family Hymenophyllaceae. The genus is accepted in the Pteridophyte Phylogeny Group classification of 2016 but not by other sources, which sink it into a broadly defined Trichomanes.
Callistopteris is a fern genus in the family Hymenophyllaceae. The genus is accepted in the Pteridophyte Phylogeny Group classification of 2016 but not by some other sources, which sink it into a broadly defined Trichomanes.
Cephalomanes atrovirens is a species of fern in the family Hymenophyllaceae. The genus Cephalomanes is accepted in the Pteridophyte Phylogeny Group classification of 2016, but not by some other sources. As of October 2019, Plants of the World Online sank the genus into a broadly defined Trichomanes, while treating the subtaxa of this species as the separate species Trichomanes acrosorum, Trichomanes atrovirens, Trichomanes boryanum and Trichomanes kingii.
