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Class I. FILICINAE. Ferns. Varens. 



Subclass I. Ophioglossales. 



Sporangia with thick walls, borne on a spike-like 

 appendage of the fertile frond. 



Only i S. A. genus : Ophioglossum. 



Subclass II. Filices Eusporangiatae. 



Isosporous. Sporangia with thick walls, formed 

 of several layers of cells. Leaves large, with two basal 

 appendages resembling stipules. 



Only i S. A. genus : Marattia. 



Subclass III. Filices Leptosporangiatae. 



Sporangia originating from single cells ; the walls of 

 the adult sporangium consisting of a single layer of cells. 



i. Order Filices. True Ferns. 



Isosporous. Sporangia mostly with annulus. 



Vernation mostly circinate. 



2. Order Hydropterides. Water- ferns. 

 Heterosporous. 



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