406 



BENNETTITALES 



[CH. 



surrounded by spirally disposed bracts (fig. 529). A whorl of 

 18 or 19 nearly mature microsporophylls is attached to the 

 base of the receptacle (figs. 528, 530) ; each microsporophyll 

 has a strong rachis extending beyond the apex of the flower-axis 



FIG. 530. Cycadeoidea dacotensis. Transverse sections through a bisporangiate 

 strobilus. A, showing the receptacle with its interseminal scales and ovules, 

 the continuous disc of microsporophylls, m, with vascular bundles, and the 

 separate (m') infolded portions of the microsporophylls with some synangia; 

 bracts and ramenta. B, this section, cut above the apex of the receptacle, 

 shows the microsporophylls and synangia. (After Wieland.) 



and bent inwards and downwards with the distal end tucked 

 between the ascending rachis and the receptacle. The slender 

 pinnules, in two alternate series, are bent downwards and bear 



