J. SMITH ON THE GENERA OF FERNS. 55 



or SO small that it soon becomes obliterated by the enlarge- 

 ment of the sporangia ; and, as both these tribes contain 

 genera analogous in habit, venation, form and position of the 

 sori, it becomes difficult, in the absence of the indusium, to 

 determine in which tribe those species so circumstanced should 

 be placed. From much observation it appears to me that 

 many species described as belonging to Polypodiece are true 

 AspidiecB, particularly among those hitherto placed jin the 

 genus Polypodium and Goniopteris ; these two genera being 

 analogous to Lastrea and Nephrodium in Aspidiecv. 



16, Synammia. Presl. J, Sm. 



(Polypodii sp. Cav.) 



Veins pinnately forked, the lower exterior vejiide free and 

 fertile, the others angularly anastomosing, forming a row of 

 elongated oblique areoles. Sporangia terminal. Sori oblong- 

 linear, oblique, transversely uniserial Fronds 8 to 12 inches 



high, pinnate, 2?innce sessile, adnate, entire, crenate or sinuose 

 or lohed. Sporangia occupying the upper part of the free 

 venules, terminating in the costal areoles. 



Species. S. triloba. Presl. 



Ohs. This approaches Grammitis both in texture and form 

 of the sori, but differs in having anastomose veins. It is 

 evidently allied to that genus, through such species as Poly- 

 podium grammitidis. Presl has also placed under Synam- 

 mia the Grammitis elongata of Swartz ; but that fern differs 

 from Synammia triloba not only in habit but also in venation. 

 I have removed it to the genus Phlehodium. 



17. GoNioPHLEBiUM. Prcsl. J. Sm. 



(Polypodii sp. Auth. Marginaria. Presl.) 

 Veins forked or costaeform and pinnate, the lower exterior 

 venule free and fertile, the others angularly anastomosing and 

 producing from their junction an excurrent, free, generally 

 fertile veinlet. Sporangia terminal. Sori round, naked or 

 squaraiferous, arranged in one or more transverse parallel 

 rows. — Rhizoma creeping. Fronds simple, pinnatijid or 



