50 



LIST OF THE BRITISH 



XXVII. Mesogloia. 

 Frond filiform, much branched, gelatinous. 



1 . Mesogloia vermicularis. 



2. ,, Grifnthsiana. 



3. virescens. 



XXVIII. Leathesia. 



Frond tuber-shaped. Spores attached to the coloured 

 tips of the filament. 



1. Leathesia tuberiformis (Corynephora ma- 



rina). 



2. „ Berkeleyi. 



XXIX. Ealfsia. 



Frond crustaceous. Fructification depressed warts 

 scattered over the upper surface, containing obovate 

 spores. 



1 . Ealfsia verrucosa (E. deusta). 

 XXX. Elachistea. 



Frond parasitical, consisting of a dense tuft of oliva- 

 ceous filaments, arising from a tubercular base, com- 

 posed of vertical fibres. 



