2 INTRODUCTION. 
small compass, and the uniformity of treatment ensured by ad- 
herence to one fixed formula of distribution, will be found advan- 
tageous to phyto-geographers. All the leading facts are thus 
placed ready for use, whether it be wished to compare the 
botanical geography of Britain with that of any other country,— 
or, to compare one part of Britain with any other part of itself, 
under the like view,—or, to compare the distribution of one 
species with that of another, or with the distribution of all others 
by means of general lists. 
Many of such comparisons have been shown in the fourth 
volume of the Cybele Britannica. Those readers who may desire 
to see and understand such an application of the details of geo- 
graphical botany, can readily do so by consulting that fourth 
volume ; which may be regarded, indeed, as a second volume also 
to the present more epitomized work. The three earlier volumes 
of the Cybele Britannica having been longer in print (1847— 
1852) their details were brought up of course less near to the 
actual knowledge of to-day; while the later date of the fourth 
volume (1859) places it less in arrear, and more especially so on 
account of the more generalised character of its contents. The 
present work will be understood to replace the three earlier 
volumes of the Cybele Britannica almost exclusively, and with 
only brief explanations drawn from the fourth volume and the 
Supplement. But it is not simply an epitome of these three 
volumes; being in fact almost a re-written work on a similar 
plan. 
1. TopoGRAPHICAL DIvIsrons. 
For the purposes of phyto-geography it was found expedient to 
form and name some other partitions of the surface of Dritain, 
besides those in current use for social or political geography. The 
three antient divisions of the island—England, Wales, Scotland— 
were too few and too unequal; while ninety counties and islet- 
groups were too numerous, and also too unequal, for some of the 
objects. Intermediate divisions were especially required, and 
these were easily formed by uniting the counties into less numerous 
