BRITISH FERNS . 
Fern (Scolopendrium vulgare) ; the Brake Fern, “Brack¬ 
en” (Pteris aquilina ) ; Hard Fern (Blechnum boreale or 
B. spicani ); Limestone Polypody (Polypodium Roberti- 
anum or P. calcareum ); the Alpine Polypody 
(Polypodium alpestre ); the Mountain Parsley or Rock 
Brake (Allosorus crispus ); Common Prickly Shield 
