57 





^'^1' 



Fig. 98. Cystopteris fragilis f. dickieana. F^rom left to right: proximal face 

 (optical section, x 250); sclerine stratification (x 2()()()); lateral, longitudinal 



view(x 1000); LO-patterns. 



DANAEA: see Fig. 144 F, p. 79. 



DAVALLIA:— 





Fig. 99. Davallia canadensis. Proximal face (x 250); lateral, longitudinal 

 view (X 1000), and exine stratification (x 2000). 



DENNSTAEDTIA: 





Fig. 100. Dennstaeiltia jmnctilobnla. From left lo right: sclerine stratification 

 (X 2000); proximal face, surface and section (x iboO); analysis of laesura. 



