Cyatheales in the context of "Fern"

In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only plants that are usable as lumber, or only plants above a specified height. Wider definitions include taller palms, tree ferns, bananas, and bamboos.

Trees are not a monophyletic taxonomic group but consist of a wide variety of plant species that have independently evolved a trunk and branches as a way to tower above other plants to compete for sunlight. The majority of tree species are angiosperms or hardwoods; of the rest, many are gymnosperms or softwoods. Trees tend to be long-lived, some trees reaching several thousand years old. Trees evolved around 400 million years ago, and it is estimated that there are around three trillion mature trees in the world currently.

Tree ferns are arborescent (tree-like) ferns that grow with a trunk elevating the fronds above ground level, making them trees. Many extant tree ferns are members of the order Cyatheales, to which belong the families Cyatheaceae (scaly tree ferns), Dicksoniaceae, Metaxyaceae, and Cibotiaceae. It is estimated that Cyatheales originated in the early Jurassic, and is the third group of ferns known to have given rise to tree-like forms. The others are the extinct Tempskya of uncertain position, and Osmundales where the extinct Guaireaceae and some members of Osmundaceae also grew into trees. In addition there were the Psaroniaceae including Tietea in the Marattiales, which is the sister group to all the leptosporangiate ferns.

Other tree ferns include Leptopteris and Todea in the family Osmundaceae, which can achieve short trunks under a metre tall. Osmunda regalis is sometimes considered a tree fern. Fern species with short trunks in the genera Blechnum, Cystodium and Sadleria from the order Polypodiales and smaller members of Cyatheales like Calochlaena, Cnemedaria, Culcita, Lophosoria and Thyrsopteris are also considered tree ferns. The species Ctenitis sloanei (Florida tree fern) from Florida, Mexico, Bermuda and the Caribbean is sometimes called a tree fern. Like all ferns, tree ferns reproduce by means of spores formed on the undersides of the fronds.

The Cyatheaceae are a family of ferns, the scaly tree ferns, one of eight families in the order Cyatheales in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the family may defined much more broadly (Cyatheaceae sensu lato) as the only family in the Cyatheales, with the PPG I family treated as the subfamily Cyatheoideae. The narrower circumscription is used in this article.

The family includes the world's tallest tree ferns, which reach heights up to 20 m. They are also very ancient plants, appearing in the fossil record in the late Jurassic, though the modern genera likely appeared in the Cenozoic. Cyatheaceae are the largest family of tree ferns, including about 640 species. Cyatheaceae and Dicksoniaceae, together with Metaxyaceae and Cibotiaceae, do not form a strongly supported monophyletic group and could be paraphyletic, but several individual subgroups are well supported as being monophyletic. Cyatheaceae are leptosporangiate ferns, the most familiar group of monilophytes.

Metaxya is a neotropical genus of ferns in the order Cyatheales. It is the only genus in the family Metaxyaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the genus may be placed in the subfamily Metaxyoideae of a more broadly defined family Cyatheaceae, the family placement used in Plants of the World Online as of November 2019.

The species of the genus are characterized by large fronds that approach 8 ft (2.5 m) in length.

Cibotium (from Greek κιβώτιον, kibṓtion, "little chest" or "box"), also known as manfern, is a genus of 11 species of tropical tree ferns. It is the only genus in family Cibotiaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the family may be treated as the subfamily Cibotioideae of a very broadly defined family Cyatheaceae, the family placement used for the genus in Plants of the World Online as of November 2019.

Ctenitis sloanei (commonly known as the Florida tree fern, red hair comb fern, Bermuda cave fern, or Florida lacefern) is a species of wood fern native to USA (Florida), Bermuda, Cuba, the Caribbean, Mexico, Central America, and northwestern South America. Although it does not belong to the order Cyatheales (the group that contains most tree ferns), it is still considered by some to be a type of tree fern. This would make it the only tree fern native to the continental United States (the parts of the US that exclude Hawaii, Alaska and overseas territories). A member of the genus Ctenitis, it was formerly classified under the genus Dryopteris as Dryopteris ampla. The population of this fern has been damaged and it is noted to possibly be endangered.