Abstract
The in situ spore ultrastructure of fossil Marattia asiatica (Kawasaki) Harris, a common Early Mesozoic marattialean fern in Asia, is investigated using scanning and transmission electron microscopes based on the material from the Lower Jurassic Hsiangchi Formation in Hubei, China. The exospore consists of a thin inner layer, a thick homogeneous outer layer, and an intermediate zone (middle layer). The intermediate zone comprises some very thin sheets linked to the inner layer and interbedded with sporopollenin similar to that composing the outer layer and includes small cavities connected to the wall surface through narrow canals crossing over the outer layer. No perispore elements were observed in the investigated spores. Comparisons of the exospore ultrastructures, especially those of the intermediate zone in extant and fossil ferns, indicate close affinities between fossil M. asiatica and the extant Marattiaceae. Such affinities are less evident for the Paleozoic fossil record of marattialeans, probab...
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
