214 DIPTEROID FERNS [CH. 



were profusely perforated— which is the actual fact for C. triaispis. The 

 parenchyma of the rhizome is crowded with nests of black sclerenchyma: 

 but these are not continuous strands, and they extend only a short way up 



Fig. 722. rt = a whole plant of Christopteris triaispis Christ, one-sixth of its natural size. ^ = basal 

 region of the fertile blade, with scheme of its branching. Reduced to \. 



