Gleichenia
Template:Short description Template:Automatic taxobox
Gleichenia is a genus of ferns.[1] Its closest relative is the genus Stromatopteris,[2] restricted to New Caledonia.
Description
These ferns have creeping rhizomes. The compound eaves fork multiple times, with the final leaf lobes ending in a pinnate arrangement. The sori are found at the bottom of the leaves and are made of a few sporangia. They are not covered by an indusium (protective covering).[3] The sori occur in a unique chamber in the laminar pits - a feature found only in this genus.[4]
Fossil record
The fossil record indicates that this genus had emerged by the late Jurassic period, although it was far more common in the early Cretaceous period.[5] There is some evidence that it may have emerged even earlier - in the upper Triassic period.[6] There are, however, multiple genera in the fossil record that show a similar leaf branching pattern to Gleichenia, which can make it difficult to determine the exact identity of a specimen that does not have adequately preserved fruiting bodies.[7]
Fossils have been found in across a wide geographic range including:
- The Pariwar formation in India (Jurassic-Cretaceous boundary)
- Gardeshwar in India (early Cretaceous)[8]
- The Silty Beds of Bedfordshire in England (early Albian age, early Cretaceous).[9]
- The USA (Cretaceous)[6]
- New South Wales, Australia (Miocene epoch, Neogene period)[4]
Phylogeny
The following species are recognised as of February 2023:[10][1][11][12]
Phylogeny of Gleichenia[13][14] Script error: No such module "Clade".
Unassigned species:
- Gleichenia alstonii Holttum
- Gleichenia elongata Baker
- Gleichenia matthewii Holttum
- Gleichenia paleacea (Copel.) Holttum
- Gleichenia peltophora Copel.
- Gleichenia ×punctulata Colenso
- Gleichenia vulcanica Blume
References
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- ↑ a b Script error: No such module "citation/CS1".
- ↑ Pryer, K. M., E. Schuettpelz, P. G. Wolf, H. Schneider, A. R. Smith, and R. Cranfill (2004). Phylogeny and Evolution of Ferns (Monilophytes) with a Focus on the Early Leptosporangiate Divergences. American Journal of Botany 91 (10): 1582–98.
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External links
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