10 



POLYPODIACEAE 



Sporangia borne at or near 

 the apices of unconnected 

 veins. 



Sori not marginal, dorsal : 

 indusium not formed in 

 part of the leaf-margin. 

 Sori narrow, linear to el- 

 liptic : indusium more 

 than thrice as long as 

 broad. 



Sori broad, roundish or 

 reniform : indusium 

 less than twice as 

 long as wide. 

 Sori mostly on the backs 

 of the veins : indusia 

 attached at or near 

 the middle, opening 

 all around : leaf-blades 

 simple or compound, 

 the leaflets not articu- 

 late, persistent. 

 Sori terminal on the 

 veins : indusia at- 

 tached at the side, 

 opening laterally, 

 mostly towards the 

 margin of the leaflet : 

 leaf-blades once-pin- 

 nate, the leaflets ar- 

 ticulate and deciduous. 



V. ADIANTEAE. 



VI. BLECHNEAE. 



VII. DHYOPTERIDEAE. 



VIII. NEPHBOLEPIDEAE. 



I. ACBOSTICHEAE. 



Erect plants with entire leaflets. 1. ACBOSTICHUM. 



II. POLYPODIEAE 



Veins free : leaf-segments usually 



numerous. 2. POLYPODIUM. 



Veins anastomosing : leaf-segments 



few or leaf-blades entire. 



Leaf-blades broad, pinnatilid. 3. PHLEBODIDM. 



Leaf-blades narrow, elongate, not 



pinnatifid, essentially entire. 4. CAMPYLONEUBCM. 



III. VlTTABIEAE 



Veins obscure, forming a single row 

 of areolae without included vein- 

 lets. 5. VlTTABIA. 



IV. PTERIDEAE 



Indusium double, an inner mem- 

 branous portion arising from the 

 receptacle : leaf-blades more than 

 twice-pinnate. 6. PTEBIS. 



