1864.] LAWSON ON CANADIAN FERNS. 263 



fanciers, and stimulate to renewed diligence in investigation. The 

 whole number of species enumerated is seventy-four. Of these 

 eleven are doubtful. Farther investigation will probably lead to 

 the elimination of several, of the doubtful species, which are 

 retained for the present with a view to promote inquiry ; but a few 

 additional species, as yet unknown within the boundaries of 

 Canada, maybe discovered. The above number may be regarded, 

 then, as a fair estimate — perhaps slightly in excess — of the actual 

 number of ferns and filicoid plants existing in Canada. The 

 number certainly known to exist, after deducting the species of 

 doubtful occurrence, is sixty-three. 



The number of species described in Professor Asa Gray's exhaus- 

 tive Manual, as actually known to inhabit the northern United 

 States, that is to say, the country lying to the south of the St. 

 Lawrence River and Great Lakes, stretching to and including Vir- 

 ginia and Kentucky in the south, and extending westward to the 

 Mississippi River, is seventy-five. This number does not include 

 any doubtful species. 



The number described in Dr. Chapman's Flora, as inhabiting 

 the Southern States, that is, all the states south of Virginia and 

 Kentucky and east of the Mississippi, is sixty -nine.^"^ 



From these statements it will be seen that we have our due 

 share of ferns in Canada. 



The whole number of ferns in all the American States, and the 

 British North American Provinces, is estimated, in a recent letter 

 from Mr. Eaton, as probably over 100. 



In the British Islands there are about 60 ferns and filicoid plants* 

 In islands of warmer regions the number is greatly increased. 

 Thus ]\Ir. Eaton's enumeration of the true ferns collected by 

 Wright, Scott, and Hayes, in Cuba, embraces 357 species. The 

 proportions of ferns to phanerogamous plants in the floras of dif- 

 ferent countries are thus indicated by Professor Balfour, in the 

 Class-Book of Botany, page 998, §1604 : — " In the low plains of 

 the great continents, within the tropics, ferns are to phanerogamous 

 plants as 1 to 20 ; on the mountainous parts of the great conti- 

 nents, in the same latitudes, as 1 to 8, or 1 to 6 ; in Congo as 1 to 27 ; 

 in New Holland as 1 to 26. In small islands, dispersed over a 

 wide ocean, the proportion of ferns increases ; thus while in 



• Mr. D. C. Eaton, M.A., is author of that portion of Dr. Chapman's 

 Flora which relates to the ferns. 



