66' 



A TERK BOOK TOR EVERYBODY. 



forms in which portions of the fronds have the appear- 

 ance of being eaten away by slug or snail. 



THJE SHIELD FEBNS. 



Clusters of spore-cases circular, and their coverings circular, attached from 

 the centre. 



The Shield Terns have derived this name from the 

 circular shield-like form of the coverings to the round 

 clusters of spore-cases. The botanical name of Polystichum 

 is, like the rest, derived from the Grreek, and means lite- 

 rally " many-rowed." 



There is a certain peculiarity of appearance in these 

 ferns, which will impress itself upon the observer, and 

 soon lead him to distinguish the ordinary forms, without 

 much trouble, from the other British ferns. 



The clusters of spore-cases are round, as in the Poly- 

 podies, but differ from them in possessing a proper cover- 

 ing (indusitm). The clusters are also round, or nearly 

 so, in the Boss Perns, and possess a covering ; but the 

 differences between these and the Shield Perns are, that 

 the covering in the Shield Perns is circular, and in the 

 Boss Perns kidney-shaped; moreover, in the Shield Perns 

 the cover is attached by the middle, and in the Boss Perns 

 by the notched or indented side. 



There are three British species, which may generally 

 be distinguished in the following manner : 



Holly Perit, with undivided or simple leaflets, toothed 

 at the edges ; 



Prickly Shield Perk, with distinct leaflets, wedge- 

 shaped at the base, but not stalked ; 



Soft Shield Per^^, with distinct leaflets, obtusely 

 angular at the base, stalked. 



HOLLY PEEN.* 



The prickly appearance of this fern is very suggestive 

 of its name. The fronds are produced in tult& from 



Polystichum. JnnnJiitia. Roth. 



