468 



BENNETTITALES 



[CH. 



similar to those of Williams onia : this portion is 6 mm. in diameter 

 and 1 cm. long. A whorl of separate cuneate microsporophylls 

 forms a hypogynous ring below the basal interseminal scales: 

 each sporophyll is attached by a narrow base (fig. 570) and bears 

 5 6 reniform synangia containing microspores. The flower is 

 thus bisexual : it affords no conclusive evidence of the occurrence 

 of any covering bracts like those of most Bennettitalean flowers. 

 In young specimens the microsporophylls are closely packed 



FIG. 570. Williamsoniella coronata. Dia- 

 grammatic sketch of a microsporophyll 

 in section and in side-view. (After 

 Thomas; x 3.) 



FIG. 569. Williamsoniella coronata. 

 Vertical section of the flower 

 showing the pyriform axis with 

 small megasporophylls and inter- 

 seminal scales and the microsporo- 

 phylls with synangia. (After 

 Thomas; x 2.) 



round the axis (fig. 571, B). The flower-stalks reach a length of 

 3-5 cm. and are 3 mm. in diameter. Fig. 571, C, shows a receptacle 

 from which the sporophylls have fallen: the microsporophylls 

 having been no doubt attached to the collar-like swelling at the 

 base. Towards the apex the axis becomes broader and at * a 

 few interseminal scales are left: above these is the apical disc 

 (corona) characterised by longitudinal ribs. An apical disc is 



