J. SMITH ON THE GENERA OF FERNS. 189 



to be orbicular. I have examined species so characterized, 

 and have usually found it to be more or less approaching to, 

 and even sometimes truly reniform ; and it appears to me that 

 due care has not at all times been taken by authors in their 

 descriptions and figures of the indusium, and even supposing 

 the indusium in a few cases to be orbicular yet I cannot ad- 

 mit the difference between reniform and orbicular, to be of 

 sufficient importance as a generic distinction alone in this 

 group of AspidiecB, This view prevents rae from adopting 

 the genus Cyclodium of Presl, constituted upon three species 

 characterized as having orbicular indusia. 



87. Mesochl^na, R. Br. 

 (Polypodii sp. Wall. Sphaerostephanos, J. Sin.) 



Veins costaeform, pinnate; venules (the lower pair) angu- 

 larly anastomosing, the others free; sporangia medial; sori 

 oblong-linear ; indusium linear, attached longitudinally on the 

 middle of the sorus, its margins free and glandulous. 



Fronds 2 to ^ feet high, pinnate ; pinncB 6 — 7 inches long, 

 linear-lanceolate, pinnatifid, villous ; venules parallel ; sori 

 becoming conjluent, the sides of the indusium then becoming 

 vertical. 



Species. 1. M. Moluccana, R. Br. 2. M. javanica, R. Br. 

 3. M. asplenioides, J. Sm. (Sphaerostephanos, J. Sm. Poly- 

 podium villosum, Wall.) Ulust. Hook, et Bauer Gen. Fil, 

 t. 24. 



Obs. When I first characterized this genus in Hooker and 

 Bauer's Genera Filicum, under the name of SphcerostephanoSy 

 I was not aware that it was the structure alluded to by Mr 

 Brown in his observations on Polypodium in Horsfield's Flora 

 Java. I also took a wrong view of the indusium, which was 

 on account of my specimen being too far advanced. I viewed 

 it as a peculiar kind of receptacle; but the examination of 

 additional specimens have enabled me to see its true structure. 

 The habits of the species are quite analogous to many species 

 of Nephrodium, the linear sori being the only character that 

 distinguishes it from that genus, the glandulous margin of the 



