Cycadales of the English Wealden

Abstract

ABSTRACT Cycadales in the English Wealden fossil flora are revised and attributed to about 34 species. The geological and evolutionary history of fossil cycads and the nature of extant cycads are outlined. Short reviews summarise the geological setting and previous work on the Wealden flora. 16 leaf species, 12 of them new, are assigned to 8 existing form-genera and one newly erected leaf genus; 4 new species of scale-leaves. A new species of megasporophyll, a new female cone species with ovules, a male cone species containing pollen and 2 large trunk species are described as named species. Nine types of isolated seeds are distinguished and described. The morphology and cuticular anatomy of extant cycad organs, selected for their similarity to the fossil species, are described, figured and compared to their Wealden counterparts. Reconstructions are presented for the leafy shoot of Nilssonia, the female cone Zamiostrobus, and the male cone Androstrobus.