A NEW LATE DEVONIAN ACUPULATE PREOVULE FROM THE TAFF GORGE, SOUTH WALES

A new genus of acupulate preovule from the Late Devonian of South Wale s is described and named Aglosperma quadrapartita Hilton et Edwards, g en. et sp. nov. Each preovule is solitary on a pedicel. The integument comprises four lobes fused to each other in the chalazal third or les s of the preovule length. The nucellus is entirely free from the integ ument. It is variable in form, although all specimens have the same in tegumentary characteristics. The new preovule adds to disparity in tha t it has morphological features not known in other Late Devonian preov ules, the majority of which are borne in cupules. However, in the abse nce of earlier records of seed plants and of information on the morpho logy and anatomy of entire plants, it is impossible to determine wheth er the new preovules were part of the initial phase in seed-plant radi ations from a common ancestor or whether they provide evidence for a p olyphyletic origin for the gymnosperms.