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THE BRITISH FERNS. 



*' Sweet to muse upon His skill display'd 

 (Infinite skill) in all that He has made ! 

 To trace in Nature's most minute design 

 The signature and stamp of power Divine ; 

 Contrivance intricate, express'd with ease, 

 Where uninstructed sight no beauty sees ! "' 



Genus I. POLYPODIUM^ or POLYPODY. 



The Polypodies, which bear the Latin name of Polypo- 

 dium, are known from all the other British Ferns, by their 

 having the spore-cases arranged in little round patches 

 placed here and there on the back of the frond, these 

 patches not being at any time, or at any stage of their 

 development, covered by the membranous film which, it 

 has already been explained, is called the indusium ; hence 

 they are said to be naked, or non-indusiate. This family 

 includes five distinct kinds, as well as many variations of 

 the common sort. In the common species the fronds con- 

 tinue green through the winter, so that it is an evergreen 



