44 INTRODUCTORY EXPLANATIONS. 



and climate. Six types of distribution were particularly- 

 mentioned ; under one or other of which, it was thought, 

 nearly all the species of plants indigenous in Britain 

 might respectively be arranged. No attempt, however, 

 was made to define the precise limits of the types geogra- 

 phically. Nor, indeed, could any exact boundary lines be 

 traced on a map, without abruptly cutting asunder the fine 

 gradations of Nature ; for the types pass into each other 

 without any hard or abrupt lines of distinction. In slight- 

 ly describing the several types, in the former volume, a 

 different order of succession was adopted, and conse- 

 quently the nos. afiixed to them were different also ; but 

 in other respects they were essentially the same as the 

 following : — 



1. The British Type. — In this group will be included 

 those species which are found in all, or nearly all, of the 

 eighteen provinces before explained; and which, more- 

 over, are not so exclusively prevalent or predominant in 

 any particular portion of the island, as to bring them 

 clearly within one or other of the following types. Some 

 of the species may be regarded as of universal occun'ence 

 in this country, growing in all the eighteen provinces, 

 probably in every county, and even in all the six ascend- 

 ing zones of vegetation or climate also. Few species, 

 however, even of this most general type, are so very gene- 

 ral in their distribution. By far the larger portion of spe- 

 cies have a restricted zonal range. Many, too, which are 

 general with reference to the provinces, are absent from 

 some of the counties. A.nd a considerable number of 

 species which are too widely and abundantly distributed 

 to allow of their being placed under any of the other types, 

 are yet rare or wholly wanting in one or more of the pro- 

 vinces; particularly in the northerly provinces of Scotland, 

 and more especially in that of the North Isles, which has 



