POLYPODIUM. 71 



The sori mostly circular, transverse, uniserial, solitary or 

 irregular. 



The rhizoma creeping, and in some examples coespitose. 



There is a great diversity of size, form, and habit. 



According to Mr. Smith, there are about a hundred true 

 Polypodiums scattered over the world. 



GONIOPTERIS. Presl. 



The veins are costceform, pinnate, the lower pinnae anasto- 

 mosing angularly. 



The sporangia is medial or costal. 



Sori circular, usually placed on or near the middle of the 

 venules, or basal, or subterminal. Khizoma creeping. 



The Ferns known under the name of Goniopteris are mostly 

 analogous to the Aspidiums iu habit, in the venation, and in 

 the form and position of the sori. The Aspidimn differs only 

 in having a special indusium. 



GONIOPHLEBIUM. Presl. 



The veins are forked, or costoe-form, and pinnate. Except 

 the lower exterior venule, which is free; the venules anastomose 

 angularly. 



The sporangia is terminal. 



The sori circular, arranged in one or more transverse parallel 

 rows. Phizoma creeping. 



Distinguished from Goniopteris by the sori being produced 

 on the apex of the lower venule, or upon the excurrent free 

 veinlets, which terminate in the areoles. 



CYPTOPHLEBIUM. R. Brown. 



The veins are forked or costceform and pinnate; the lower 

 exterior venule (of each fascicle) free and fertile, the remainder 

 arcuately or angularly anastomosing. 



Sporagia lateral or terminal. 



Sori round, naked, arranged in two rows between and parallel 

 with the veins, or irregular. 



Distinguished from Gonioplilehium by having smooth fronds 

 and distinct sori. 



