104 CTCABOPHYTA. 



closely allied, if not identical genera. It may, as I have already 

 suggested, be a convenience to retain both designations, or to use 

 Williamsonia as a subgenus ol Bennettites. iN'athorst has also 

 expressed the opinion that the two types may be closely allied. 

 Another question which has been dealt with by several authors is 

 the precise nature of the Williamsonian inflorescence : "Williamson 

 believed that the specimens of Williamsonia ■which he described 

 represented both male and female flowers, and that the plant 

 Williamsonia gigas agreed with existing Cycads in being diceoious. 

 Solms-Laubach expressed the opinion that Williamson's specimens 

 represent the male flowers, and this view was taken also by 

 Saporta and JfTathorst. On the other hand, I stated my opinion 

 that the Yorkshire fossils described as Williamsonia gigas are 

 imperfectly preserved female inflorescences. This conclusion has 

 been arrived at also by Professor Lignier,^ whose work has done 

 much to increase our knowledge of th« Bennettitales ; he has 

 recently published a memoir based, in part, on an examination of 

 the Yates specimens in Paris, in which he states his opinion in 

 favour of regai-ding Williamsonia gigas, as represented by the 

 reproductive shoots described by "Williamson, as the female 

 inflorescence. The fossils referred to by "Williamson as male 

 flowers Lignier believes to represent portions of ovulifetous flowers. 

 During the last few years Mr. "Wieland," of Newhaven, has 

 published several papers on the reproductive organs of American 

 plants belonging to the genus Bennettites, and has contributed 

 most important facts in regard to the nature of the reproductive 

 organs. He has demonstrated the occurrence of fertile shoots 

 bearing in the centre more or less aborted ovules, and at the 

 periphery pinnate leaves with numerous sporangia agreeing closely 

 with the sori of recent Marattiaceous ferns. I hope to deal at 

 greater length with the general morphology and systematic 

 position of the Bennettitales in a memoir, now in preparation, 

 to be published by the Palseontographical Society. 



The Jurassic rocks of England dealt with in this volume have 

 not afforded any specimens of Bennettitean flowers, with the 



Lignier (03). 

 "Wieland (99), (99=). 



