CRYPTOGAMIA 

 CLASS XXIV. 



THE PA UTS OF FRUCTIFICATION OBSCURE 

 OR UNKNOWN. 



This Class has four natural Orders. 



ORDER I. 



PRICKLY POLYPODIUM. This fern is a na- filtges. 

 live of most parts of .Europe, and grows in shady Fern*. 

 places. 



Polypodium is the botanical term .for that Genus 

 of plants commonly called Ferns, and of which there 

 are enumerated no less than one hundred and thirty- 

 seven species, the greater part of American growth. 

 The investigation of this extensive Genus is attended 

 with difficulty, from their general resemblance and 

 habit, and from the obscurity of their specific cha- 

 racters. 



This Class includes many genera, besides those 

 which are called ferns, in the common acceptation 

 of the word, as Adder's-tongue, Rough Horse-tail* 

 Spleen-wort, &c. 



