THE LIME-STONE POLYPODY. 



Polypodium caleareum.* SMITH. 



The Lime-stone Polypody differs from 

 the Oak Fern in its stouter, erecter, and 

 more rigid habit, and in the mealy-looking' 

 glandulosity of its surface ; yet still more 

 in that the division of its fronds is pinnate 

 rather than into three distinct branches. 

 The fronds are also of a duller and deeper 

 green, and without the marked deflection 

 of the rachis. And instead of the branches being 

 rolled up into three balls, the young pinnse curl in on 

 their rachides and the entire frond upon its rachis, so 

 that the frond is of the ordinary bipinnate structure. 



* Also P. Robertianum, P. Dryopteris, Lastrea calcarea, Lastrea 

 Robertianum, Phegopteris calcarea, &c. 



