Gleichenia
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| Gleichenia | |
|---|---|
 | |
| Gleichenia microphylla, Mornington Peninsula, Victoria | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Division: | Polypodiophyta |
| Class: | Polypodiopsida |
| Order: | Gleicheniales |
| Family: | Gleicheniaceae |
| Genus: | Gleichenia Sm. |
| Type species | |
| Gleichenia polypodioides (L.) Smith | |
| Species | |
| Synonyms[1] | |
| |
Gleichenia is a genus of ferns.[2] Its closest relative is the genus Stromatopteris,[3] restricted to New Caledonia.
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).[4] The sori occur in a unique chamber in the laminar pits - a feature found only in this genus.[5]
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.[6] There is some evidence that it may have emerged even earlier - in the upper Triassic period.[7] 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.[8]
Fossils have been found in across a wide geographic range including:
- The Pariwar formation in India (Jurassic-Cretaceous boundary)
- Gardeshwar in India (early Cretaceous)[9]
- The Silty Beds of Bedfordshire in England (early Albian age, early Cretaceous).[10]
- The USA (Cretaceous)[7]
- New South Wales, Australia (Miocene epoch, Neogene period)[5]
