3 o6 



KEY TO THE GENERA. 



* FRUITING FRONDS PARTLY STERILE. 



2. Fruiting portion in the middle of the 

 frond. Interrupted fern. 



OSMUNDA. 30 



2* Fruiting portion at the apex of the 



frond. 



a. Sterile pinnae palmate ; rachis 

 twining. Climbing fern. 



LYGODIUM. 280 



a. Sterile pinnae pinnate ; fronds 

 large ; fertile portion green, soon 

 turning brown. Royal fern. 



OSMUNDA. 32 



2. Fruiting portion apparently on a sep- 

 arate stalk, above the sterile. 

 6. Sterile portion entire, thick ; fer- 

 tile, a simple spike. Adder's 

 tongue. 



OPHIOGLOSSUM. 45 



6. Sterile portion more or less di- 

 vided ; fruit in racemes or panicles 

 occasionally in spikes. Moonwort : 

 Grape ferns. 



BOTRYCHIUM. 



