108 III. INTRODUCED SPECIES. 



the species in the present work, having been given in the 

 former list, four other terms are here substituted, for 

 more ready comparison with the definitions and terms 

 used by Henslow and Babington ; from which they still 

 differ, however, in one respect, that of placing two de- 

 grees (possibly and probably introduced) between the 

 native and certainly introduced species. The incognits 

 or discarded species of the Cj'^bele are left out of the 

 lists. The abbreviations are intelligible enough, being 

 simply the three first letters in the series of terms. It is 

 to be kept in recollection that the indications in this first 

 column are general ; relating to the whole of Britain. 



The Second column, where numerals are employed, is 

 founded upon twenty-eight local lists of plants, for small 

 tracts of country, spotted about various parts of Britain, 

 from the southern coasts of England, northwards to 

 Nairn and Elgin in Scotland. All these lists are marked 

 so as to distinguish the local conditions of the species 

 into three categories or classes ; namelj^, native — du- 

 biously native — introduced. The number of such lists, 

 among the whole twenty- eight, in which the species are 

 so noted, is shown in the column of numerals. It will 

 be seen by the cipher that many of the distrusted natives 

 are absent from all the twenty-eight local tracts ; while 

 others are found in only few of them ; circumstances 

 which do not tend to lessen the distrust of their true 

 nativitj^ The history of these twenty-eight lists is 

 shortly thus. In order to obtain a greater amount of 

 information about local botany, than could be acquired 

 from the published Floras and other data alone, printed 

 lists of British plants were sent to manj'^ of the provincial 

 botanists, with a request that they would mark the names 

 of species known to them as occurring within a defined 

 space. Most usually the area selected was that com- 



