FERNS; 



BRITISH AND EXOTIC. 



PTERIDE^E. J. Smith. 



This extensive class of Ferns contains the genus Hypolepis, 

 species with large and handsome fronds; the genus Cheilanthes, 

 a very pretty tribe of plants, some of which are covered 

 beneath the frond with dense farinose powder; Platyloma, a 

 very varied and handsome tribe; Adiantum, known generally 

 as the Maiden-hair Ferns, the most delicate-looking of any 

 tribe; Litobrochia, an extensive genus; Pteris, mostly large and 

 elegant Ferns; Onychium, a small but interesting family; Lomaria, 

 having fertile fronds, different in form from the barren fronds; 

 Blechnum and Doodia, singular Ferns; and Woodicardia, a 

 small but elegant genus. 



In the Pteridece the sori are circular or elongated, and trans- 

 verse, marginal, intramarginal or costal, simple, except when they 

 become confluent, when they are compound. The sori have a 

 special lateral indusium, which is produced on the exterior side 

 of the sporangiferous receptacle. Its inner margin is free. 



The Pteridece are at once known from the Polypodiacece by 

 the special indusium. 



VOL. III. n 



"V*v 



