236 



THE SPORE-PRODUCING ORGANS 



[CH. 



Fig. 236. Types of indusium in the Polypodiaceae. A — Peranetrta cyatheoides, Don, with inferior 

 indusium, centrally attached, on the stalked sorus. B = Hypoderris Brownii, J. Sm., indusium 

 inferior, centrally attached. C=Aspleniuni bulbiferum, Forst. , indusium lateral, with linear attach- 



