PTERIDOPHYTA 



157 



Angiosperrnse 



Heterosporese 



Leptosporangiatse 

 Isosporeae 



Heterosporeae 



Cycadaceae 



Heterosporeae 



Isosporeae 



Isosporeae 



Coniferas (?) 



Heterosporeae 



Isosporeas 



Eusporangiatae 



Horsetails Ferns Club-mosses 



(Equisetineae) (Filicineae) (Lycopodineae) 



Liverworts 

 (Hepaticae) 



Diagram to illustrate the relationships between the three existing 

 classes of Pteridophytes and the Spermatophytes. 



