title: Morphological and Ultrastructural Studies on in situ Spores of Oligocarpia (Gleicheniaceae) from the Lower Permian of Xinjiang, China.
abstract: Though the fossil genus Oligocarpia is generally regarded to be of gleicheniaceous affinity, nothing is currently known about its spore ultrastructure. In this article, the micromorphology and ultrastructure of in situ spores of gleicheniaceous affinity are investigated for the first time with scanning electron microscopy and transmission electron microscopy from a compression specimen of Oligocarpia kepingensis Wang and Wu collected from the Lower Permian of Xinjiang, northwest China. Spores of O. kepingensis closely resemble the dispersed taxon Leiotriletes (Naumova) Potonié et Kremp. At the ultrastructural level, the exospore consists of three-layered subdivisions, including a degraded and weakly preserved thin inner layer, a complex and elaborate middle layer, and homogeneous outer layer. Comparisons are made between Oligocarpia spores and those of other related fossils, as well as extant taxa based on morphological and ultrastructural evidence. These data indicate that, despite clear differences in leaf morphology, O. kepingensis has a close relationship to the family Gleicheniaceae.
authors.initials: Y
authors.lastname: Wang
authors.initials: G
authors.lastname: Guignard
authors.initials: G
authors.lastname: Barale