ON GENERA AND SPECIES. 39 



and age of individual plants of the same species. Further 

 investigations, however, are required before the vascular 

 structure of the stipes can be made of service as a distin- 

 guishing character for either genera or species, and this 

 can only be satisfactorily obtained by a series of observa- 

 tions of living plants. 



M. Fee gives a systematic arrangement of his method of 

 classification, which occupies nearly five double-columned 

 pages ; but the many divisions, sub-divisions, figures, 

 letters, and arterisk, renders it necessary to be very care- 

 fully studied before it can be well understood. The fol- 

 lowing is sufficient to show M. Fee's mode of classifying 

 genera, from which it will be seen that plants most 

 opposite in natural habit are associated, consequent on 

 characters derived from the form and position of the sori, 

 and in being naked or indusiate and the different forms of 

 the latter, and therefore cannot be considered otherwise than 

 as an artificial arrangement of complicated construction. 



Abstract of Fee's arrangement : 



ORDER POLYPODIACE^E. 



I. CATHETOGYRATEJ;. 

 Acrosticheae, Gen. 19. (Ex. Acrostichum, Platycerium, 



Leptochilus.) 

 Lomarieae. Gen. 8. (Ex. Blechnum, Acropteris, Hymen- 



olepis.) 

 Vittarieae. Gen. 10. (Ex. Pteropsis, Drymoglossum, 



Lemogramma.) 

 Pleurogrammeae. Gen. 5. (Ex. Monogramma, Adeno- 



phorus, Xiphopteris.) 

 Pterideae. 



1. Lindsayeae. Gen. 5. (Ex. Isoloma, Schizoloma, 

 Dictyoziphium) . 



