240 THE CANADIAN NATURALIST. 



now hope will not be delayed many years longer), would be much 

 too bulky and expensive for the main purpose which this Manual 

 fulfils. For its purpose, the present geographical limitation is, on 

 the whole, the best,— especially since the botany of the states 

 south of our district has been so well provided for by my friend, 

 Dr. Chapman's Flora of the Southern States, issued by the same 

 publishers. The southern boundary here adopted coincides better 

 than any other geographical line with the natural division between 

 the cooler-temperate and the warm-temperate vegetation of the 

 United States ; very few characteristically Southern plants occur- 

 ring' north of it, and those only on the low coast of Virginia, in the 

 Dismal Swamp, etc. Our Western limit, also, while it includes a 

 considerable prairie vegetation, excludes nearly all the plants 

 peculiar to the great Western woodless plains, which approach 

 our borders in Iowa and Missouri. Our northern boundary, being 

 that of the United States, varies through about five degrees of 

 latitude, and nearly embraces Canada proper on the east and on 

 the west, so that nearly all the plants of Ccinada East on this side 

 of the St. Lawrence, as well as those of the deep peninsula of 

 Canada West, will be found in this volume. 



" Distinction of Grade of Varities. Vain is the attempt to draw 

 an absolute line between varieties and species. Yet in systematic 

 works the distinction has to be made absolute, and each particular 

 form to be regarded as a species or a variety, according to the 

 botanist's best judgment. Varieties, too, exhibit all degrees of 

 distinctness. Such as are marked and definite enough to require 

 names are distinguished here into two sorts, according to their 

 grades: 1. Those which, I think, cannot be doubted to be 

 varieties of the species they are referred to, have the name printed 

 in small capitals. These varieties make part of the common 

 prragraph. 2. Those so distinct and peculiar that they have 

 been, or readily may be, taken for species, and are some of them 

 not unlikely to establish the claim : of these the name is printed 

 in the same [black letter] type as that of the species ; and they 

 are allowed the distinction of a seperate paragraph, except where 

 the variety itself is the only form in the country." 



The whole work is a model of accurate description, correct 

 orthography and typographical excellence. W. 



Published, Montreal, 1st January, 1868. 



