490 



A TEXTBOOK OF THEORETICAL BOTANY 



■^. 







Leaf 



Placenta 



Sporangium 



Indusium 



Fig. 478. — Dryopteris-fiUxmas. Transverse section of pinnule through 

 a sorus showing developing sporangia. 



5-^. 



'-'"'--r Leaf meristele 



\ \ 



ink. 



# 





IP 



^^•^ 



Annulus 



Water gland 

 Placenta 



Indusium 



Fig. 479. — Dryopteris filix-mas. Transverse section of pinnule through 

 a sorus showing mature sporangia, some of which are dehiscing. 

 (From Kny.) 



