Academic literature on the topic 'Cycadophytes'

The Early Cretaceous continental sediments in the East Coast of India are characterized by the Ptilophyllum flora. Interplay of tectonism and sedimentation caused plant fossil preservation in different unconnected paralic deposits distributed in Cauvery, Palar, Krishna-Godavari and Mahanadi basins and in the associated Pranhita-Godavari Graben. Plant megafossils assigned to pteridophytes, pteridosperms, cycadophytes, Taxales, Ginkgoales and Coniferales are variously distributed in these basins. Differential preservation of plant parts denotes an incomplete evolutionary pattern. Variation within the basinal flora reflects a localised aspect. Plant fossils preserved in the Cauvery, Palar, Krishna-Godavari and Mahanadi basins reflect a near shore continental sedimentary fill subjected to more dynamic events like marine transgression, which probably did not allow better preservation of plant fossils. Paucity of carbonised/silicified material, abundance of impressions of plant leaf fossils, scarcity of wood and reproductive parts indicate an unfavourable environment for plant fossil preservation in these pericratonic basins. Whereas in the associated Pranhita-Godavari Graben the plant fossils are better preserved in the sub-aerially exposed basinal areas away from the main coast-line. The Early Cretaceous flora of Cauvery, Palar and Krishna-Godavari basins dominated by cycadophytes suggests presence of seaward margins of fluviodeltaic palaeoenvironment. The pteridophyte dominant flora of Mahanadi Basin represents a decreasing marine influence contrary towards the south-eastwards. The evolution and diversification of the East Coast Early Cretaceous flora runs parallel to other intracratonic basinal flora. The uniformity in the floral component supports an equable climate. Conifers being the upland floral elements constitute chief components of intracratonic basinal flora. The fluviomarginal elements like cycadophytes predominate the pericratonic sedimentation with some upland near basinal taxa. Pteridosperms and Ginkgoales are scanty. Presence of leaves with entire margin indicates a favourable growth environment.

Leaf-associated fungi, the fungi that depend on leaves to sporulate, have a rich Cenozoic record, however their earlier diversity is poorly characterized. Here we describe<i>Harristroma eboracense</i>gen. et sp. nov., a Middle Jurassic leaf-associated fungus colonizing the leaf cuticle of<i>Nilssonia tenuicaulis</i>(cycadophyte). To place our newly described species into a picture of the diversification of Mesozoic fungi, we reassess fossils with leaf-associated stromata in the context of fungal molecular phylogeny. Being melanized, with radiate stromata, and on leaves,<i>H. eboracense</i>and other fossils from the Jurassic and earlier periods are probably related to filamentous<i>Ascomycota</i>in the superclass<i>Leotiomyceta.</i>Characters needed for further resolution of leaf-associated fungal biology and classification, such as the presence of an ostiole for spore discharge and appressoria for entry into leaf tissue first appear in the Mesozoic fossil record. Among Early Cretaceous fossils,<i>Spataporthe taylorii</i>represents the oldest unambiguous evidence of perithecial<i>Sordariomycetes</i>while<i>Protographum luttrellii</i>and<i>Bleximothyrium ostiolatum</i>are the oldest<i>Dothideomycetes</i>thyriothecia. Environmental observations show that broad leaved gymnosperms (especially cycadophytes) growing in warm temperate wet forests might have been the first environment for the radiation of<i>Leotiomyceta.</i>

The plant megafossil assemblage of Gollapalle Formation, Andhra Pradesh is enriched and updated. The flora is chiefly constituted of Cladophlebis, Sphenopteris, Marattiopsis, Pachypteris, Taeniopteris, Ptillophyllum, Dictyozamites, Pterophyllum, Williamsonia, Bucklandia, Elatocladus, Pagiophyllum, Brachyphyllum and Araucarites. Conifers and cycadophytes are dominant: pteridophytes and pteridosperms are poorly represented. Early Cretaceous age is supported for the Gollapalle flora.

The present paper deals with megafloral investigation of Bartala locality of Rajmahal Basin. Nine taxa are recorded for the first time from this locality: Hausmannia, Taeniopteris, Anomozamites, Pterophyllum, Pseudoctenis, Dictyozamites, Ginkgoites, Desmiophyllum. Elatocladus and Brachyphyllum. The assemblage is dominated by cycadophytes, pteridophytes and conifers are scarcely represented. Predominance of Anomozamites in this assemblage perhaps shows the local variation. On the basis of assemblage correlation, an Early Cretaceous age has been suggested.