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Gleichenia
''Gleichenia'' is a genus of ferns. Its closest relative is the genus '' Stromatopteris'', 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). The sori occur in a unique chamber in the laminar pits - a feature found only in this genus. 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. There is some evidence that it may have emerged even earlier - in the upper Triassic period. 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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gleichenia Punctulata
''Gleichenia'' is a genus of ferns. Its closest relative is the genus ''Stromatopteris'', 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). The sori occur in a unique chamber in the laminar pits - a feature found only in this genus. 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, Cretaceous period. There is some evidence that it may have emerged even earlier - in the upper Triassic, Triassic period. 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 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
