ON WOODSIA, mo 



A NEW GENUS OF FERNS. 



There is perhaps no tribe of cryptogamous plants 

 which since the time of Linnaeus has received greater 

 additions to its number of species, or more considerable 

 improvements in its systematic arrangement, than the 

 Filices ; and certainly no botanist has so essentially con- 

 tributed to these improvements as the President of this 

 Society ; whose ingenious Essay on Dorsiferous Ferns may 

 justly be considered as the groundwork of the more com- 

 plete dissertations of Professors Swartz and Bernhardi, 

 which have appeared since its publication. 1 



Linnaeus, in his latest work, the 13th edition of the Sgs- 

 tema Vegetabilium, enumerates scarcely more than 200 

 Ferns, which he referred to twelve genera : while the 

 Species Plantarum of the late Professor Willdenow contains 

 upwards of a thousand plants of the same order, arranged 

 under forty-three genera. It is however remarkable, that 

 of this vast number of species nearly one half belong to 

 four of the Linnean genera, namely, Poly podium, Acrosti- 

 chum, Aspleniam, and Pteris, all of which were first pro- 

 posed by Ray in his Metliodus Plantarum Emendata, pub- 

 lished in 1703; without names, indeed, but with cha-cm 

 meters nearly similar to those of Linnaeus. 



It appears, therefore, that the arrangement of Ferns at 

 present universally followed is not wholly new : and that 

 it has not attained such a degree of perfection as to super- 



1 An. 1793, in Mem. de VAcademie Royale des Sciences de Turin, vol. v, 

 p. 401. 



