156 J. SMITH ON THE GENERA OF FERNS. 



examples, and also with the genus Drpostachium, which ap- 

 proaches the present genus in its somewhat amorphous-look- 

 ing sori. 



It is highly probable that there is only one species of the 

 genus, and that P. simplex is only an imperfect or starved 

 form of the originally observed species. The smooth, shining 

 aspect of the sterile pinnae of this fern may without exami- 

 nation upon first sight be taken for the leaves of some exogen. 



48. Gymnopteris, Bernh. Presl. 

 (Acrostichii sp. Auth. Leptochilus, Kaulf. Hymenolepis, 



Kaulf.) 

 Veins uniform or costseform. Venules compoundly anas- 

 tomosing and producing variously directed straight or curved 

 free veinlets. 



Fronds simple entire, or pinnate. Pinnae entire or sinuous, 

 generally membraneous, and adherent to the rachis. Sporangia 

 universal on the under side. Fertile frond sometimes spiciforrn, 

 with revolute conniving indusiiform margins, 



Examp. 1. G. spicata (Acrostichum, Linn. Hymenolepls 

 ophioglossoides, Kaulf.) 2. G. axillaris {Leptochilis, Kaulf.) 

 3. G. platyrynchos; J. Sm. 4. G. quercifolia, Bernh. 5. 

 G. nicotianifolia; {Sw.) 6. G. aliena ; {Sw.) 7. G. acumi- 

 nata; {Willd.y 



Illust. Hook. gen.Jil. t. 85. 



Obs. The habit of this genus is somewhat similar to Cyrto- 

 gonium, but differing in the more irregular and compound 

 anastomosing of the venules, and which is analogous to the 

 PhyllitidfE section of Drynaria, with which the present genus 

 also agrees in habit. 



Tribe III, Pteride/e, J. Sm. 

 Sori round, or elongated, and transverse, marginal, intra- 

 niargmal or costal, simple, or by confluence compound, fur- 

 nished with a special lateral indusium, which is produced on 

 the exterior side of the sporangiferous receptacle, i^s inner 

 margin free. 



