Type: Peer Reviewed Research Paper Journal: Journal of Asian Earth Sciences Year: 2013 Authors: Spencer ART, Wang S-J, Dunn MT, Hilton J. DOI 10.1016/j.jseaes.2013.07.030 Abstract: The medullosan pteridosperm ovule Stephanospermum Brongniartis a well-known component of Carboniferous aged coal-ball and siderite nodule floras from North America and Europe but also occurs in the Permian floras of Cathaysia […]