X INTEODUCTION. 



ACROGENiE PTERIDOID^, Pteridoid Acrogens, or 



Ferns and their allies, are plants of vascular structure, 



but wliich produce fruit without preliminary flowers : 



they may be divided thus : — 



FILICALES have distinct leaves bearing one-celled 



capsules which are encircled by an elastic ring : 



they comprise : — 



Ehizophyllace^, in which the leaves are attached to 



a rhizome or root. 

 CoEMOPHYLLACE^, in which the leaves are attached to 

 a cormus or trunk. 

 OSMUND ALES have distinct leaves and one-celled 

 capsules detached from the leaves, and not encir- 

 cled by an elastic ring : they comprise : — 

 OsMUNDACE^, in which the vernation of the leaves is 



circinate and the trunk woody. 

 Ophioglossace^, in which the vernation of the leaves 

 is straight and the trunk succulent. 

 LYCOPODIALES have distinct leaves and capsules 

 divided by one or more septa : they comprise : — 

 Maesiliace^, in which the capsules are attached to 



the rhizome or root. 

 LYCOPODiACEiE, in which the capsules are seated in 

 the axils of the leaves. 

 EQUISE TALES have no leaves, but consist of an arti- 

 culated branched stem : they comprise : — 

 Equisetace^, in which the fructification forms a ter- 

 minal spike. 

 Chaeace^, in which the fructification is seated in the 

 axils of the branches. 



It will be seen that the divisions Rhizophyllacefe and Cor- 

 mophyllacese have a great similarity to those proposed by Mr. 

 John Smith, of Kew, under the names of Eremobrya and 



