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Stellar evolution is the process by which a star changes over the course of its lifetime and how it can lead to the creation of a new star. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the current age of the ...
Pteridospermatophyta, also called "pteridosperms" or "seed ferns" are a polyphyletic [1] grouping of extinct seed-producing plants.The earliest fossil evidence for plants of this type are the lyginopterids of late Devonian age. [2]
In a vascular plant, the stele is the central part of the root or stem [1] containing the tissues derived from the procambium. These include vascular tissue, in some cases ground tissue and a pericycle, which, if present, defines the outermost boundary of the stele.
The evolution of the MADS-box family has been extensively studied. These genes are present even in pteridophytes, but the spread and diversity is many times higher in angiosperms. [63] There appears to be quite a bit of pattern into how this family has evolved. Consider the evolution of the C-region gene AGAMOUS (AG).
In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is one of eight in the order Cyatheales, and has three genera. [1] In the classification of Christenhusz & Chase (2014), the family is the only one in the order Cytheales, the families of PPG I being reduced to subfamilies. It then has 13–14 genera. [2]
The Pteridophyte Phylogeny Group (PPG) is an informal international group of systematic botanists who collaborate to establish on the classification of pteridophytes (lycophytes and ferns) that reflects knowledge about plant relationships discovered through phylogenetic studies. In 2016, the group published a classification for extant ...
In 2016, the Pteridophyte Phylogeny Group divided order Polypodiales into six suborders. Pteridaceae is the sole family in suborder Pteridiineae, with 52 genera. The suborder has the same circumscription as Smith et al. used for the family. The phylogenetic relationship between these six suborders is shown in this cladogram: [2]
In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is placed in the suborder Polypodiineae. [1] Alternatively, it may be treated as the subfamily Dryopteridoideae of a very broadly defined family Polypodiaceae sensu lato. [2] The family contains about 1700 species and has a cosmopolitan distribution.