Thelypteridaceae
Encyclopedia
Thelypteridaceae is a family of about 900 species of fern
s.
The ferns are terrestrial
, with the exception of a few which are lithophyte
s (grow on rocks). The bulk of the species are tropical, although there are a number of temperate species.
These ferns typically have creeping rhizome
s. The frond
s are simply pinnate
to pinnate-pinnatifid. There is either no frond dimorphism
or only mild dimorphism, either open venation or very simple anastomosing. The sori
are mostly reniform in shape and have indusia, except for the Phegopteris group.
because of the sorus shape. However, there are a great many differences between the groups, and these plants are now segregated in their own family.
Some researchers include the entire family Thelypteridaceae in the genus Thelypteris
; others divide the family into as many as 30 genera. An intermediate position is to place the bulk in Thelypteris (which can then be divided into subgenera and sections corresponding to the genera of other authors) but to separate out Phegopteris
and Macrothelypteris. Another choice is to divide the family into a half a dozen or so genera.
This family includes several complexes of species that are difficult to distinguish, and seem to represent a remarkable evolutionary radiation.
Recent genetic
evidence shows that the family is clearly monophyletic
. The same genetic studies show that the traditional genus Phegopteris is, in fact, a clearly segregate group that diverges at the very base of the family tree
. In fact, this particular clade
also includes the genera Pseudophegopteris and Macrothelypteris, which are here included in the larger genus Phegopteris
. Similarly, Coryphopteris is included here in the genus Metathelypteris, Parathelypteris is included in Amauropelta, and a large group of genera are included in Cyclosorus
.
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
s.
The ferns are terrestrial
Terrestrial plant
A terrestrial plant is one that grows on land. Other types of plants are aquatic , epiphytic , lithophytes and aerial ....
, with the exception of a few which are lithophyte
Lithophyte
Lithophytes are a type of plant that grows in or on rocks. Lithophytes feed off moss, nutrients in rain water, litter, and even their own dead tissue....
s (grow on rocks). The bulk of the species are tropical, although there are a number of temperate species.
These ferns typically have creeping rhizome
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
s. The frond
Frond
The term frond refers to a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group...
s are simply pinnate
Pinnate
Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts...
to pinnate-pinnatifid. There is either no frond dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
or only mild dimorphism, either open venation or very simple anastomosing. The sori
Sorus
A sorus is a cluster of sporangia .In fungi and lichens, the sorus is surrounded by an external layer. In some red algae it may take the form of a depression into the thallus....
are mostly reniform in shape and have indusia, except for the Phegopteris group.
Classification
At one time, all thelypterioid ferns were included in the genus DryopterisDryopteris
Dryopteris , commonly called wood ferns, male ferns, and buckler ferns, is a genus of about 250 species of ferns with distribution in the temperate Northern Hemisphere, with the highest species diversity in eastern Asia. Many of the species have stout, slowly creeping rootstocks that form a crown,...
because of the sorus shape. However, there are a great many differences between the groups, and these plants are now segregated in their own family.
Some researchers include the entire family Thelypteridaceae in the genus Thelypteris
Thelypteris
Thelypteris is a genus of ferns in the family Thelypteridaceae. If the genus is defined fairly broadly, it contains 875 species, many of which are extremely similar to one another, and is found nearly worldwide. The ferns are terrestrial, with the exception of a few which are lithophytes...
; others divide the family into as many as 30 genera. An intermediate position is to place the bulk in Thelypteris (which can then be divided into subgenera and sections corresponding to the genera of other authors) but to separate out Phegopteris
Phegopteris
Phegopteris is a genus of ferns known collectively as the Beech ferns. Traditionally this genus included only the first three species listed...
and Macrothelypteris. Another choice is to divide the family into a half a dozen or so genera.
This family includes several complexes of species that are difficult to distinguish, and seem to represent a remarkable evolutionary radiation.
Recent genetic
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
evidence shows that the family is clearly monophyletic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
. The same genetic studies show that the traditional genus Phegopteris is, in fact, a clearly segregate group that diverges at the very base of the family tree
Family tree
A family tree, or pedigree chart, is a chart representing family relationships in a conventional tree structure. The more detailed family trees used in medicine, genealogy, and social work are known as genograms.-Family tree representations:...
. In fact, this particular clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
also includes the genera Pseudophegopteris and Macrothelypteris, which are here included in the larger genus Phegopteris
Phegopteris
Phegopteris is a genus of ferns known collectively as the Beech ferns. Traditionally this genus included only the first three species listed...
. Similarly, Coryphopteris is included here in the genus Metathelypteris, Parathelypteris is included in Amauropelta, and a large group of genera are included in Cyclosorus
Cyclosorus
Cyclosorus is a genus of 3 species of ferns. in the Marsh Fern Family; Cyclosorus interruptus, Cyclosorus lenormandii and Cyclosorus striatus....
.