430 



BENNETTITALES 



[CH. 



receptacle some sterile megasporophylls and scales remained 

 (fig. 548, as, dl). 



Williamson regarded the funnel-shaped depression as the 

 impression of the lower surface of a laterally expanded portion of 



Fig. 546. Williamsonia gigas. A, apical portion of flower. B, cast of A; a, per- 

 sistent interseminal scales. C, flower in longitudinal section. C, interseminal 

 scales from the base. (Williamaon Collection, Botany School, Cambridge.) 



the axis of the flower, and to this expansion he gave the name 

 lenticular disc (figs. 546, 547, a). It is, however, much more 

 likely that the apparent extension of the axis is due to the 



