Vlll. 



that all that go by the name of new discoveries, were really 

 so. If we take Mr. Moore's useful and laborious "Index 

 Filicum " as a test of the numerical statistics of Ferns, the 

 number appears great indeed. The eleventh part of this 

 " Index " has recently been issued, bringing the Catalogue 

 down to the letter C, and to the end of the genus Cuspidaria. 

 Thus the work at present only embraces the Genera (alpha- 

 betically arranged) of the first three letters of the alphabet 

 (A — C). These include 47 Genera and 1069 species! The 

 total of such genera to be recorded are 186, of which about 

 one-eighth only have been elaborated, so that if we consider 

 the remaining seven-eighths of the genera to possess the 

 same proportional amount of species, which may possibly be 

 the case, this brings us to 8000 different kinds of Ferns 

 described in books by persons worthy of credit from their 

 name and character; to say nothing of the multitudes of 

 synonyms, which are legion. 



But it must be recollected that Mr. Moore necessarily 

 reckons, as species of authors, a great number which he has 

 no means of verifying, nor of judging whether they ought, or 

 ought not to be rejected, as he has done in the case of many 

 others : — and of which there is too much reason to fear that a 

 large proportion would come into the latter category. If we 

 reckon the number of well-ascertained Ferns at half the 

 amount enumerated in the "Index Filicum," viz. at 4000 

 species, it will perhaps nearly accord with the truth. 



Nothing will so much tend to a correct knowledge of these 

 as accurate figures, published on a cheap scale, as are the two 

 " Centuries " now uuder consideration : — and we have had 



