Jir. GBNEEA OF PEBNS: 



Teias. Indasium linear, plane, membranaceous, yariously directed 

 in the solitary sori, opening face to face in the conniyent ones. 

 yeins anastomosing in few angular unequal areoles near the costa, 

 and emitting simple or forked free marginal venules or veinlets. 



Fronds simple, herbaceous, caudate and rooting at the apex. 

 Rhizome short, erect. — Small ferns of peculiar aspect, remarkable 

 for the variously directed irregularly-disposed, yet usually more 

 or less distinctly opposite sori, on each side the costa. 



Ex. : C. rMzophyllas, Lk. | ? C. sibiricus, SuprecM. 



(c) Indusia connate in pairs, hack to hacTc. 

 * Veins free. 



72. DIPLAZIUM, Swartz, Schrad. Jown. 1800, ii. 4, 61 ; 

 Id. St/n. Fil. 91, t. 2. 



LoTZEA, KlotzachandKa/raten; AspLENll sp,, .^ucf . ; Scolopbndeii sp., 

 Auct,; AiLAIfTODli Sp., Auct.; CaXLIPTEEIDIS Sp., Bory; HEMIOiaTIDIS 



sp., Stcartz ; AjnsoGOiril sp., Hooker; MicEOSTEGiiE sp,, Fresl; Htpo- 

 CHLAmnjis sp., J^c ; Athteii sp., Auct. 



Sori iadusiate, linear, all or the lowermost only double, i.e., 

 the receptacles occupying both sides of the veins. Indusiwm 

 narrow, membranaceous, plane or fornicate ; in the double sori 

 affixed in pairs back to back on opposite sides of the same 

 venule, one opening anteriorly, the other posteriorly; in the 

 simple sori, as in Aspleniwm. Veins simple or forked from a 

 central costa ; venules direct, free. 



Fronds herbaceous or coriaceous, simple pinnate or variously 

 compound. Ehizome short, erect, rarely sub-arborescent. — The 

 limit between Asplenium and the present genus is not very 

 definite, in consequence of some species having but few of the 

 double sori ; notwithstanding which, Diplazium has been almost 

 universally admitted since the time of Swartz, by whom it was 

 founded. We do not refer it back to Asplenium, as Mettenius 

 has recently proposed to do, because that genus is already suffici- 

 ently unwell dy, and the double indusium affords a tangible mark 

 of distinction. We include all species which produce twin sori 

 with any degree of constancy, on the same principle that ferns 



