312 CHARACTERS OF TRIBES AND GENERA. 



fronds contracted, bipinnate, segments baccaeform, compactly 

 filled with sporangia, which rise from four to six puncti- 

 form receptacles, each furnished with a lateral, cucullate, 

 membraneous indusium. 



Type. Onoclea sensibilis, Linn. 



Illust. Hook, and Bauer, Gen. Fil., t. 82 ; Moore, Ind. 

 Fil., p. 65 A. ; J. Sm., Ferns, Brit, and For., fig. 106 ; 

 Hook., Syn. Fil., t. 1, fig. 9. 



OBS. This genus, as here restricted, consists of a solitary 

 species of peculiar habit and somewhat doubtful relation- 

 ship. In my Arrangement of 1841, and previously (1838), 

 in a note at tab. 82 of Hooker and Bauer's "Genera 

 Filicum," I stated that the membraneous scales found inter- 

 posed between the confluent sori were truly special laterally 

 attached indusia, and I therefore placed it in proximity 

 with Aspidium, thus removing it from the vicinity of Blech- 

 num and Woodwardia, where it originally stood, but later 

 and more careful examination of the natural affinities of 

 Ferns, has led me to place it again in the tribe Blecknece, 

 its nearest ally being the genus Lorinseria. 



In the " Species Filicum " the genus Struthiopteris is 

 united with Onoclea, but it is quite at variance with Onoclea 

 technically as well as in habit. 



Sp. 0. sensibilis, Linn, (v v.) 



A native of North America. 



179. STENOCHLJINA, J. Sm. (1841). 

 Acrostichum auct., Hoo~k. Sp. Fil. 



Vernation uniserial, distant, sarmentum elongated, scan- 

 dent. Fronds 2 to 3 feet long, of two forms, the sterile 

 pinnate, the fertile contracted, pinnate or bipinnate ; pinnae 

 articulated with the rachis, Feins rising from an obscure 



