2. P0LYP0DIACE2E. [1. Nephbodjum- 



A. Sori roundish f dorsal. Indusium roundish 



attached by its centre or a sinus, rarely 



evanescent, or present in some sori and absent 



in others. 

 Indusium kidney-shaped or evanescent. Veins not 



anastomosing, or only the tips joining those 



from the next costa 1. Nephrodium. 



Indusium peltate. Veins copiously anastomosing 2. Aspidium^ 



B. Sori roundish close to the margin or marginal, 



not confluent. Indusium present. 

 Sori sub-apical on the lobes, indusium attached by 

 base and sides 8. Odontosoria>K 



Sori within the margin, indusium attached by the 

 base only ........ 4. Humata, 



C. Sori elongate dorsal, straight or curved. Indusium 



present. 

 Sori attached sideways to the fertile veins • . 5. Asplenium. 



Sori short. Indusium often curved or hook* 

 shared over the vein ...... 6. Athyrium. 



Sori continuous along the rachis of the pinna . 7. Blechnum. 



D. Sori linear, close to the margin Or marginal. 



1. Stipes not black and polished. 



Sori on a marginal nerve, with a marginal 

 indusium . . . . • . .8. Pteris. 



2. Stipes black and polished. 



Pinnse not broadening apically. Sori at the 

 thickened ends of the nerves, sometimes con- 

 fluent. Leaf -margin recurved . . , .9. Cheilanthes, 



Pinnae or "leaf segments fan«shaped 

 apically) 10. Adiantum. 



E. Sori without any indusium, usually sunk in the 



frond. Stipes articulate to the rhizome . 11, Tolypodium. 



1. Nephrodinm, Schott. 



Stout ferns with the fronds more or less coriaceous. 

 Fronds 1-2-pinnate, the fertile similar to, or differing from, 

 the barren. Venation quite free, or the veins of one tooth or 

 segment uniting in an intermediate Derve w,ith those of thr 



ISO 



