Middle Bathonian floras and phytocoenoses of France

In the Causses Basin (SE France), a continental lignitic deposit yields a diverse middle Bathonian megaflora, until now almost unstudied. The floristic data include megafloras, palynology and data from woods and leafy shoots. The palaeoecology of this flora is quite unique, representing backswamps, fens, and freshwater ponds in a carbonate domain. There is little evidence of vegetation from brackish environments. Elsewhere in France, contemporaneous floras are known, with different ecologies. These include a flora of low undulating tracts on shell sand in Normandy and a mangal assemblage in Franche-Comté. New palaeobotanical and palynological data are given for both floras. The floristic composition of the three floras is compared and discussed together with additional coeval data. This set of floras is of interest as they grew mainly on calcareous soils, whereas most Middle Jurassic floristic associations described previously were mainly from siliciclastic environments. Because of their contemporaneous nature, asserted with an accuracy rarely reached for continental biota, these floras can be used to estimate the climatic gradient of the middle Bathonian.