TABLE OF GENERA. 45 



8. Aspleninm = Dorsal-fruited Perns, having the in- 



dusium straight and elongate, and attached 

 by the side towards the margin of the pinnae or 

 pinnules. 



9. CeteracJi = Dorsal-fruited Ferns, having the indu- 



sium obsolete, and the sori hidden among densely 

 imbricated, rust-coloured, chaffy scales. 



10. Scolopendrium = Dorsal-fruited Perns, having the 



sori elongate, and proximate in parallel pairs, the 

 indusium opening along the centre of the twin 

 sorus. 



D. PTERIDE,E = Perns, the margin of whose fronds is 

 either soriferous, and continuously or interruptedly 

 changed into a special indusium, or whose spore- 

 cases are in lines parallel with the margin. It con- 

 tains the genera Pteris, Adiantum, and Blecknum. 



11. Pteris = Dorsal -fruited Perns, having the spore- 



cases in a continuous line at the edge of the 

 frond, beneath an indusium formed of the altered 

 margin. 



12. Adiantum = Dorsal -fruited Perns, having the 



spore-cases in patches, on the reflexed, altered 

 apices of the lobes of the fronds. 



