XVI International Botanical Congess

Three sporocarp specimens dn several hundred dispersed megaspores were collected from the Eutaw Formation (Santonian) along Upatoi Creek, Georgia, USA. On the basis of shared morphological features of the sporocarp wall structure, and in situ megaspore and microspore ultrastructure and ornamentation, these specimens are assigned to the water fern family, marsileaceae. If found dispersed, the megaspores would be assigned to Molaspora lobata (Dijkstra) Hall, the microspores to Crybelosporites Dettmann. Comparison of available characters in the fossil material with extant taxa of Marsileaceae revealed a remarkable similarity to Regnellidium diphyllum Lindm. Securely linking Molaspora lobata and Crybelosporites to Marsileaceae improves our knowledge of the stratigraphic range and pattern of morphological evolution within this fern lineage.