BRITISH FERES. 27 
A A + B 0 B 
Polypodium vulgare bifido-cristatum (A)xl’. v. elegaxtissimum (B). 
P. v. elega'ntissimo-ckistatum (A + B). 
C shows a frond of the cross A + B reverting to one of the parents A, and not to the normal form. 
