3!2 NOTHOCLCENA. 



It is perhajjs desirable to state that those species whieh are 

 exceedingly rare in cultivation, will not be described until the 

 completion of the present volumes. This plan has been adopted 

 with the Gijmnograinmas for two reasons, the first, because 

 before the work is completed, other species will have been intro- 

 duced, which will render it necessary to publish a supplementary 

 volume, and the second, that by describing almost unknown 

 species as the work proceeds will defer the figuring of the Ferns 

 which are more generally known and cultivated. However, 

 unless a species is very rare, it will occupy its proper place as 

 the work progresses. 



