68 



Fig. 125. Isoetes echinosponun, 

 acetolyzed megaspore embedded 

 in glycerine jelly (x 125). In 

 some places the spiny perine is 

 faintly shown. 





Fig. 126. Isoetes adspersa; sclerine stratification 

 and LO-patterns. A thin cf. perine with hollow, 

 tapering processes, open at top (OL), is un- 

 derlain by an exine consisting of a tegillate and 

 baculate sexine (LO = bacula) and nexine. 



Fig. 127. Isoetes Imetica. a, lateral, longitudinal view (surface); b, lateral, 

 longitudinal view (optical section); c, lateral transverse view (optical section); 

 c, lateral transverse view (optical section); d, polar view (proximal face; 

 sculptine not included); c, exine from a young spore with sexine still adhering 



to the nexine; x 4000 (a-d x 1000). 



