io6 



DRYOPTEROID FERNS 



[CH. 



the sporangial stalk. The spore-output is 48, and each spore has exospore 

 and perispore. In these features Diacalpe compares closely with Dryopteris 

 filix-mas. The prothallus bears stalked glandular hairs on its lower surface, 

 while the antheridia have a segmented lid-cell (Schlumberger, /.^.). These 

 features point to a relationship with the Cyatheaceae, between which and 

 Dryopteris the genus appears to form a natural link. 



Fig. 650. A— D = Diacalpe aspidioides Bl. ^ = pinna from the upper part of the leaf, natural size. 

 j5 = a pair of pinnules, enlarged. C=sorus, cut vertically, enlarged. /? = sporangium, highly magnified. 

 E—H=Feranema cyatheoides Don. i£' = pinna from the upper part of the leaf, natural size. 7^= a pair 

 of pinnules, enlarged. 6^ = sorus, cut vertically, enlarged. Zr= sporangium, highly magnified. (B—D, 

 F—n a.htr Bauer : A, E after Diels, from Natiirl. Pflanzenfam.) 



