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
Gleichenia dicarpa leaves
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)
^ ab"Genus Gleichenia". PlantNET - New South Wales Flora Online. Royal Botanic Gardens & Domain Trust, Sydney Australia. Retrieved 2009-01-26.
^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.
^Levyns, M.R. (1966). A Guide to the Flora of the Cape Peninsula (2nd Revised ed.). Juta & Company, Limited. OCLC621340.
^Bose, M.N.; Kumaran, K.P.N.; Baneiji, J. (1982). "Pachypteris haburensisn. sp. and other plant fossils from the Pariwar Formation". Palaeobotanist. 30 (1): 1–11.
