176 GARDENS PAST AND PRESENT 



be taken, therefore, as a fairly constant rule that 

 if moisture be the first requisite for ferns, shelter, 

 more than shade, is the next thing to be provided 

 for draught being altogether contrary to the well- 

 doing even of the most hardy kinds. Filmy ferns 

 which, by natural habit, are found growing in 

 deep shade, may be regarded as exceptions but 

 though the two British species, the Killarney and 

 the Tunbridge filmy ferns, grow freely in the open 

 air in the few spots which they haunt, it is exceed- 

 ingly rare to find them doing well under cultivation 

 without artificial shelter of either a cave or glass 

 case. 



British ferns are ranged under about fourteen 

 well-defined heads or genera; but the species and 

 variations of these mount up to many hundreds. 

 Some of them, such as the depauperated varieties, 

 though exceedingly interesting to fern collectors, 

 are not beautiful from a garden point of view. 



The British ferns that are most generally suit- 

 able for outdoor culture are as follows : 



Aspidiums or Shield Ferns 



Aspleniums ,, Spleen worts 



Lomarias ,, Hard Ferns 



Nephrodiums ,, Buckler Ferns 



Osmundas ,, Royal Ferns 



Polypodiums ,, Polypodies 



Pteris ,, Brake Ferns 

 Scolopendrium ,, Hart's Tongue 



There are others which do not belong to these 

 groups, which present greater difficulties of con- 



