158 J. SMITH ON THE GENERA. OF FERNS. 



tlie crenuliform indusium being analogous to the outer or 

 accessary indusium which characterizes DicksoniecE. 



50. OCHROPTERIS, J. Sm. 

 (Adiantis, sp. Sw.) 



Feins pinnately-forked, radiating; venules direct, their 

 apices clavate ; sporangia produced on the base of the indu- 

 sium which is formed on the converging apices of two to four 

 venules, constituting oblong marginal sori. 



Fronds deltoid decompound; stipes and rachis smooth, of a 

 pale colour, idtimate pinmdes or lacinice oblong, obtuse, margi- 

 nate, cimeate at the base and decurrent, producing a solitary or 

 rarely twin sorus on their apex or sides. 



Species. O. pallens. (Adiantum, Sw, Cheilanthes daval- 

 lioides, Bory. " Ad. pallens, Siv. habitu et fructificatione 

 ab omnibus diversissimum proprium constituet genus," Kaulf.) 

 lllust. 



Ohs. The peculiar and distinct habit is the principal fea- 

 ture that marks this as not forming a natural combination 

 with any of the neighbouring genera. It has hitherto been 

 placed in Adiantum, but the situation of the sporangia does 

 not agree with that genus. With more propriety it might 

 be placed in the genus Pteris so far as the sori are concerned, 

 but it does not agree with any species of Pteris in habit ; it 

 may therefore be viewed as forming a transition with these 

 genera through Onychium. In habit it comes nearest Ilypole- 

 pis, but differs in the sori being seated on the apices of two 

 to four con verging- venules, as in some species of Adiantum. 



51, Cheilanthes, Sw. J. Sm. 



Veins forked ; venules direct, their apices free and sporan- 

 glferous. Sori round, marginal, solitary or contiguous. 

 Indusium usually reniform, rarely oblong, and including more 

 than one sorus. 



Fronds bi-tripinnate, smooth, pilose, glandulose or squamose, 

 pmnules sometimes very small and orbicidar; stipes usually 

 ebeneous. Sori often becoming confiuent. 



