The 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, 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 and Tietea in the Marattiales, which is the sister group to most living ferns including Cyatheales.
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.
Osmundaceae is a family of ferns containing four to six extant genera and 18–25 known species. It is the only living family of the order Osmundales in the class Polypodiopsida (ferns) or in some classifications the only order in the class Osmundopsida. This is an ancient and fairly isolated group that is often known as the "flowering ferns" because of the striking aspect of the ripe sporangia in Claytosmunda, Osmunda, Osmundastrum, and Plensium. In these genera the sporangia are borne naked on non-laminar pinnules, while Todea and Leptopteris bear sporangia naked on laminar pinnules. Ferns in this family are larger than most other ferns.
The order Cyatheales, which includes most tree ferns, is a taxonomic order 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 from a vertical rhizome, others have shorter or horizontal expanding rhizomes.
Marsileaceae is a small family of heterosporous aquatic and semi-aquatic ferns, though at first sight they do not physically resemble other ferns. The group is commonly known as the "pepperwort family" or as the "water-clover family" because the leaves of the genus Marsilea superficially resemble the leaves of a four-leaf clover. In all, the family contains 3 genera and 50 to 80 species with most of those belonging to Marsilea.
Platycerium is a genus of about 18 fern species in the polypod family, Polypodiaceae. Ferns in this genus are widely known as staghorn or elkhorn ferns due to their uniquely shaped fronds. This genus is epiphytic and is native to tropical and temperate areas of South America, Africa, Southeast Asia, Australia, and New Guinea.
A pteridophyte is a vascular plant that reproduces by means of spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams", meaning that their means of reproduction is hidden.
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. Alternatively, the family may defined much more broadly 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.
Dicksoniaceae is a group of tropical, subtropical and warm temperate ferns, treated as a family in the Pteridophyte Phylogeny Group classification of 2016, and counting 30-40 species. Alternatively, the family may be sunk into a very broadly defined family Cyatheaceae sensu lato as the subfamily Dicksonioideae. Most of the genera in the family are terrestrial ferns or have very short trunks compared to tree ferns of the family Cyatheaceae sensu stricto. However, some of the larger species can reach several metres in height. A number of others are epiphytes. They are found mostly in tropical regions in the Southern Hemisphere, as far south as southern New Zealand. Larger tree ferns in the genus Cibotium were formerly included in Dicksoniaceae, but are now segregated as the family Cibotiaceae.
Onoclea sensibilis, the sensitive fern, also known as the bead fern, is a coarse-textured, medium to large-sized deciduous perennial fern. The name comes from its sensitivity to frost, the fronds dying quickly when first touched by it. It is sometimes treated as the only species in Onoclea, but some authors do not consider the genus monotypic.
Gymnocarpium dryopteris, the western oakfern, common oak fern, oak fern, or northern oak fern, is a deciduous fern of the family Cystopteridaceae. It is widespread across much of North America and Eurasia. It has been found in Canada, the United States, Greenland, China, Japan, Korea, Russia, and most of Europe. It is a seedless, vascular plant that reproduces via spores and have a life cycle with alternating, free-living sporophyte and gametophyte phases.
A prothallus, or prothallium, is usually the gametophyte stage in the life of a fern or other pteridophyte. Occasionally the term is also used to describe the young gametophyte of a liverwort or peat moss as well. In lichens it refers to the region of the thallus that is free of algae.
Plant reproduction is the production of new offspring in plants, which can be accomplished by sexual or asexual reproduction. Sexual reproduction produces offspring by the fusion of gametes, resulting in offspring genetically different from either parent. Asexual reproduction produces new individuals without the fusion of gametes, resulting in clonal plants that are genetically identical to the parent plant and each other, unless mutations occur.
The Hymenophyllaceae, the filmy ferns and bristle ferns, are a family of two to nine genera and about 650 known species of ferns, with a subcosmopolitan distribution, but generally restricted to very damp places or to locations where they are wetted by spray from waterfalls or springs. A recent fossil find shows that ferns of Hymenophyllaceae have existed since at least the Upper Triassic.
Onocleaceae is a small family of terrestrial ferns in the order Polypodiales. It is placed in the suborder Aspleniineae in the Pteridophyte Phylogeny Group classification of 2016. Alternatively, the family, along with Blechnaceae, may be placed in a very broadly defined family Aspleniaceae as the subfamily Blechnoideae. The family may contain from one to four genera, consisting of five species largely in north temperate climes. The four genera, Matteuccia, Onoclea, Onocleopsis and Pentarhizidium, may be included under the single genus Onoclea.
Ceratopteris is the only genus among homosporous ferns that is exclusively aquatic. It is pan-tropical and classified in the Parkerioideae subfamily of the family Pteridaceae.
Aglaomorpha is a genus of ferns in the subfamily Drynarioideae of the family Polypodiaceae. The Pteridophyte Phylogeny Group classification of 2016 uses this genus name, while other sources use Drynaria to include Aglaomorpha. Species are commonly known as basket ferns. As circumscribed in PPG I, the genus contains around 50 species.
Notholaena standleyi, also known as star cloak fern and Standley's cloak fern, is a fern that is native to the United States and Mexico. It is a member of the genus Notholaena, which is part of the subfamily Cheilanthoideae of family Pteridaceae. It is distinguished by the pentagonal shape formed by the blades of its frond, a property other members of Notholaena do not possess.
Hymenophyllum tunbrigense, the Tunbridge filmy fern or Tunbridge filmy-fern, is a small, fragile perennial leptosporangiate fern which forms large dense colonies of overlapping leaves from creeping rhizomes. The common name derives from the leaves which are very thin, only a single cell thick, and translucent, giving the appearance of a wet film. The evergreen fronds are bipinnatifid, deeply and irregularly dissected, about 3 to 6 cm long, 2 cm across with dark winged stipes. In contrast to the similar H. wilsonii the fronds are more divided, flattened, appressed to the substrate and tend to have a bluish tint.
Polyphlebium venosum, the veined bristle-fern or bristle filmy fern, is a fern in the family Hymenophyllaceae. It is only found in wet forests, mainly growing as an epiphyte on the shady side of the soft tree fern, Dicksonia antarctica. It also grows on logs, trunks of trees and rarely on trunks of Cyathea species or on wet rock-faces. It is found in the wetter parts of Eastern Australia and New Zealand. P. venosum has poor long-distance dispersal compared to other ferns due to its short lived spore. Notable features of Polyphlebium venosum include it being one cell layer thick, 5–15 cm in length, having many branching veins and a trumpet shaped indusium.
