FILICES. 21 



.a. Sporangia rather large, with a wall more than 1 layer of cells thick ; 

 ring wanting, very rarely rudimentary. (Eusporangiatae). 

 o Sporangia collected in sori placed on the under side of normal, 

 foliaceous segments of the fronds. 



IX. Mlaratiiaceae. P. 761. 

 0O Sporangia placed on much contracted, non-fohaceous, spiciform 

 or paniculiform segments of the fronds. 



X. €lpliioglossaceae. P. 771. 



