Article: The Middle Jurassic flora from Stonesfield, Oxfordshire, UK
C. J. Cleal and P. M. Rees
The Stonesfield 'Slate' of Oxfordshire has yielded a diverse Middle Jurassic flora, containing 25 morphospecies, dominated by remains of araucariacean and cheirolepidiacean conifers, bennettitaleans, and leaves of the possible gymnosperm Pelourdea. It mainly represents coastal vegetation, which included mangrove-like stands of Ptilophyllum, and conifers probably growing in lowland coastal habitats that were subjected to periodic water-stress. The Pelourdea leaves may have drifted in from drier, more upland habitats. The flora is similar, but not identical to, the slightly older floras from the Cotswold 'Slate' of Gloucestershire, such as from Eyeford and Sevenhampton. Also comparable are the contemporaneous floras preserved in marine deposits in France and the Venetian Alps of Italy. It is quite different from the Middle Jurassic flora of Yorkshire, which is thought to represent vegetation growing in deltaic habitats. The new combinations Ptilophyllum pectiniformis (Sternberg), Komlopteris speciosa (Ettingshausen) and Pachypteris macrophylla (Brongniart) are proposed for species found at Stonesfield. Nilssoniopteris solitarium (Phillips) comb. nov. is proposed for the species previously named Nilssoniopteris vittata (Brongniart). Taeniopteris vittata Brongniart is retained as the type species of Taeniopteris, a morphogenus to be used for entire cycadophyte leaves that cannot be definitely assigned to the cycads or bennettitaleans. Conites is shown to be an earlier nomenclatural synonym of Bucklandia, to be used for casts and compressions of cycadophyte stems. This requires a number of new combinations for species that have hitherto been included in Bucklandia: Conites anomala (Stokes and Webb), C. gigas (Seward), C. indica (Seward), C. milleriana (Carruthers), C. pustulosa (Harris) and C. yatesii (Carruthers).