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Ferns and relatives / Helechos y afines
Gleicheniaceae C. Presl
EOL Text
Terrestrial or lithophytic ferns. Rhizome thin, widely creeping, branched, apex with fringed scales or branched hairs. Fronds widely spaced, arranged in 1 row, scandent, with indeterminate growth. Lamina variously compound, pseudo- dichotomously branched with a dormant apical bud between the pairs of pinnae, herbaceous to coriaceous. Veins free, forked. Indumentum composed of stellate and branched hairs and fimbriate bracts confined to the rhizome and frond axes. Sori circular, superficial or immersed, on acroscopic vein branches, without indusia.
License | http://creativecommons.org/licenses/by-nc/3.0/ |
Rights holder/Author | Mark Hyde, Bart Wursten, Petra Ballings, Flora of Zimbabwe |
Source | http://www.zimbabweflora.co.zw/speciesdata/family.php?family_id=94 |
Barcode of Life Data Systems (BOLD) Stats
Specimen Records:51
Specimens with Sequences:48
Specimens with Barcodes:48
Species:28
Species With Barcodes:25
Public Records:47
Public Species:24
Public BINs:0
The forked ferns are the family Gleicheniaceae. They are sometimes – like all ferns – placed in an infradivision Monilophytes of subdivision Euphyllophytina, allowing for more precise phylogenetic arrangement of the tracheophytes. More conventionally, the name Pteridophyta, ranked as a division, is used in lieu of the Monilophytes. The formerly independent families Dicranopteridaceae and Stromatopteridaceae are nowadays generally included in the Gleicheniaceae, whereas the Dipteridaceae and Matoniaceae, though closely related, are considered spearate families by most authors.[1]
These tropical ferns are the most widespread living lineage of Gleicheniales. Their rhizomes have a "vitalized" protostele or in some taxa a solenostele. The leaves are indeterminate, with pseudodichotomously forked leaves except in Stromatopteris, and free veins. The sori are abaxial but not marginal and carry 5–15 exindusiate round sporangia each. These have a transverse-oblique annulus and contain 128 to 800 bilateral or globose-tetrahedral spores. The sori and sporangia mature at the same time, and the spores grow into surface-dwelling green prothalliums beset with club-shaped hairs.[1]
Systematics[edit]
There is some dispute about ranking these ferns. They are typically placed in the order Gleicheniales. This is alternatively be considered a subclass Gleicheniatae or class Gleichenopsida, so that a distinct taxon can be established for the leptosporangiate ferns. In this case, the Gleicheniaceae are upranked to an order and receive the name Gleicheniales. Irrespective of their modern taxonomic treatment, the Gleicheniaceae were formerly included in the order Polypodiales. But the ferns in the loose sense are much too diverse a group to be shoehorned into one taxon at such a low rank.[1]
The Triassic Antarctipteris and Gleichenipteris are sometimes ascribed to the Gleicheniaceae, but are probably better considered Gleicheniales incertae sedis.[1] The two living subfamilies contain six genera:
Subfamily Gleichenioideae
Subfamily Stromatopteridaeae
Footnotes[edit]
References[edit]
- A. R. Smith, A. R. Kathleen, M. Pryer, E. Schuettpelz, P. Korall, H. Schneider & P. G. Wolf. 2006. A classification for extant ferns. Taxon 55(3): 705–731. PDF fulltext
- C. Michael Hogan. 2010. Fern. Encyclopedia of Earth. eds. Saikat Basu and C. Cleveland. National Council for Science and the Environment. Washington, D.C.
License | http://creativecommons.org/licenses/by-sa/3.0/ |
Rights holder/Author | Wikipedia |
Source | http://en.wikipedia.org/w/index.php?title=Gleicheniaceae&oldid=591385077 |