1864.] LAWSON ON CANADIAN FERNS. 265 



Europe; C in this column indicating Continental Europe, and B 

 the British Islands. The fifth or last column (V.) shows the spe- 

 cies that extend northwards into the Arctic circle — 35 in all, of 

 which hovvever, only 14, or perhaps 15, are known to be Arctic in 

 America. Am., As., Eu,, and G., indicate respectively Arctic 

 America, Arctic Asia, Arctic Europe, and Arctic Greenland. The 

 information contained in the last column has been chiefly derived 

 from Dr. Hooker's able Memoir in the Linnsean Transactions 

 (vol. xxiii., p. 251). 



Hitherto no attention whatever has been paid, in Canada, to the 

 study of those remarkable variations in form to which the species 

 of ferns are so peculiarly liable. In Britain, the study of varieties 

 has now been pursued by botanists so fully as to show that the phe- 

 nomena which they present have a most important bearing upon 

 many physiological and taxological questions of the greatest scien- 

 tific interest. The varieties are studied in a systematic manner, 

 and the laws of variation have been to a certain extent ascertained. 

 And as the astronomer can point out the existence of a planet 

 before it has been seen, and the chemist can construct formulae for 

 organic compounds — members of homologous series — in antici- 

 pation of their actual discovery, so in like manner the pteridologist 

 now studies the variations of species by a comparative system, 

 which enables him to look for equivalent forms in the corresponding 

 species of different groups. Studies so pursued are calculated to 

 evolve more accurate and definite notions as to the real nature of 

 species, and the laws of divergence in form of which they are 

 capable. I would therefore earnestly invite Canadian botanists to a 

 more careful study of the varieties of the Canadian ferns, after 

 the manner of Moore and other European leaders in this compara- 

 tively new path. The elasticity, or proneness to variation, of the 

 species in certain groups of animals and plants has been somewhat 

 rashly used to account for the origin of species, by what is called 

 the process of variation. It seems to tell all the other way. In- 

 numerable as are the grotesque variations of ferns, in forkingsand 

 frillings, and tassellings, and abnormal veinings, &c. (see the figures 

 in Moore's works), we do not know of a single species in which such 

 peculiarities have become permanent or general, that is specific^ 

 so that the species can be traced back to such an origin. Surely 

 something of the kind would have happened had all species origin- 

 ated by a process of variation. 



