150 KEY TO THE GENERA OF FERNS 



Without indusium. 



Sporangia disiinct, borne in pinnate or compound spikes 

 or panicles. Sterile portion solitary^ variously divided, often 

 ternate and fleshy. Veins free. 



Botrychiuin^ p. iii. 



Sporangia leathery, united in two rows on the edges of a 

 simple spike. Sterile portion solitary, entire ; veins netted. 



Ophioglossum, p. 124. 



