PREFACE. ; xi 
We believe, however, that varieties such as these we have re- 
corded, have a botanical significance; that they are, in fact, items in 
the mass of evidence by which we may arrive at the conclusion that 
species generally have a wide range of form, even within narrow 
geographical limits. The variations found among plants, nearly 
related, though admitted to specific rank, often serve to connect the 
individuals into a series so extended and withal so complete, that 
the so-called species themselves seem to lose all definite limit. This 
surely indicates that these so-called species of plants are but groups 
of individuals having a certain amount of resemblance, associated by 
the Naturalist for the mere technical convenience of interchanging 
information respecting them: just as genera are undoubtedly groups 
of the so-called species collected together with the same end in 
view. Nature seems to acknowledge only the individual, while the 
species (at least such species as are now admitted and are indeed 
required for the purpose just alluded to,) is an artificial thing of 
man’s contrivance. If indeed, Nature yields her vegetable species, 
as probably she does, for the earth was created to bring forth 
grass and herb and tree “after his kind,” these must be something 
far more comprehensive than those of the botanist, and perhaps 
not such as he could employ, at least without subdivision, to carry 
out his schemes of classification. 
Applying, however, the term ‘species’ to the groups of individuals 
as usually associated under this designation, whether the association 
be natural or artificial in character, another consideration arises. 
Tf in a small area like that of Great Britain, there occur so many 
varieties, often marked, and usually constant in character, the 
variations must become much more numerous and important, if 
the species is spread, as often happens, over widely separated and 
extensive portions of the globe. Hence it may be concluded, that 

