PHYLETIC RELATIONS 



653 



Osmunaaca 



. t 

 Sofiyopterutece 



Fio. 354. 



Scheme to illustrate approximately the relations of the several families of Ferns, as 

 concluded from the discussions in ihe text. It will be noted that tin.- distinctions as 

 Simplices, Gradatae, and Mixtae traverse several of the probable evolutionary linos : 

 the grouping is so disposed that Ferns with marginal sori lie to the left, with superficial 

 sori to the right. No attempt is made to connect the lines into a phyletic tree. 



