438 



BENNETTITALES 



[OH. 



(fig. 552). The microspores, 58 65ju in length, are rather narrow, 

 ovate and very similar to those described by Solms-Laubach 1 

 in Cycadeoidea etrusca. The synangia are attached in two rows 

 to slender lateral segments which appear to be given off from the 

 upper face near the median line of the broad linear sporophylls 

 (fig. 565, A). Nathorst points out that the position of the fertile 

 pinnae brings the sporophylls into close relation with the vegeta- 

 tive fronds of Ptilophyllum pecten and other Cycadean fronds in 

 which the pinnae are attached to the upper face of the rachis. 



FIG. 552. Williamsonia spectahilis. Restoration of an almost mature male 

 flower. (After Thomas; approximately nat. size.) 



While the longer pinnae in the middle portion of a sporophyll 

 bear several synangia, those near the base and apex are shorter 

 and, in the proximal region nearer the broad cup formed by the 

 coherent bases of the sporophylls, occur singly, thus approaching 

 the condition characteristic of W. whitbiensis (fig. 565, B) in which 

 they are sessile on the simple microsporophylls. It is noteworthy 

 that in some specimens figured by Nathorst there is a tendency 



1 Capellini and Solms-Laubach (92) PL v. fig. 7. 



