CHARACTERS OF TRIBES AND GENERA. 203 



ceratum, Mett. (v v.) ; A. apiifolium, SM. (v v.) ; A. 

 coadunatum, Wall* (v v.). 



105. CTCLODIUM, Presl. (1836). 

 Aspidium, sp., auct. ; Hook. Sp. Fil. 



Vernation sub-sarmentose, hypogeous. Fronds pinnate, 

 2 to 3 feet high ; sterile pinnae broad elliptical, linear- 

 lanceolate. Veins pinnately forked ; venules acutely 

 anastomosing, producing from their angular junctions an 

 excurrent free or anastomosing veinlet ; fertile pinnae con- 

 tracted, linear lanceolate. Veins uniform, reticulated. 

 Receptacles medial, punctiform. Sori round, confluent, and 

 occupying the whole under surface. Indusium obicular. 



Type. Aspidium confer turn, Kaulf. 



Illust. Hook, and Grev., t. 121 ; Hook, and Bauer, t. 

 49, B. ; Moore Ind., p. 67, A. ; J. Sm. Ferns, Brit, 

 and For., fig. 67. 



OBS. In many points of structure this genus agrees 

 with Cyrtomium, the chief difference being the hypogeous 

 sub-sarmentose vernation, the more simply anastomosed 

 venation, and the specially contracted fertile fronds. The 

 latter character also is the chief distinction between this 

 genus and some species of Nephrodium, in which the 

 fertile fronds have a tendency to contraction. I restrict 

 Cydodium to three described species, natives of Eastern 

 Tropical America. In the " Species Filicum " Hooker unites 

 Aspidium confertum of Kaulfuss with A. meniscioides, Will- 

 denow, but judging from cultivated specimens of A. 

 confertum of British Guiana, as compared with herbarium 

 specimens of A. meniscioides from Trinidad, they appear to 

 me to represent distinct species. 



* Phlebigonium, Fee, is probably only a starved imperfect specimen 

 of this species. 



