III. INTRODUCED SPECIES. 109 



prised withiu a circle of three or more miles distance, 

 traced around their own towns or abodes ; larger spaces 

 being sometimes taken instead,, according to individual 

 preference or convenience. From the catalogues thus 

 kindly supplied, have been selected the twenty-eight used 

 in the subjoined list. Contrary to the first column, it 

 must be recollected, the second one sums up into nume- 

 rical figures the local conditions of the species. 



The Third column also exhibits the local conditions of 

 the plants, doing this singly and individually for three 

 tracts. The Collectanea for a Flora of Moray has been 

 before alluded to, as the first publication on local botany 

 in which advanced views were shown in regard to the 

 native or accidental occurrence of the species in the tract 

 of country to which it relates. Only three divisions were 

 made in that work, namely, 'native — dubious — intro- 

 duced.' But the application of the two latter of these 

 three terms is made with much freedom and clearness of 

 view. Moray is nearly equivalent to the sub-province of 

 North-east Highlands. — More recentlj^, in the Supple- 

 ment to the Flora of Yorkshire, Mr. J. G. Baker has 

 adopted the terms used in the Cybele Britannica, and ap- 

 plied them (with the necessary variations in use) to ex- 

 press the local conditions of the species in that county 

 and province. So that we can thus find two spaces in 

 the north and middle of Britain, the floras of which can 

 be compared together, with reference to questions about 

 the nativity of the species. — Henslow's Catalogue of 

 British Plants will again assist our inquiries here ; being 

 made to serve also (by marks post-fixed to the names) as 

 a list for the county of Cambridge ; and thus aftbrding a 

 third space for comparison with the other two, more 

 southward on the same side of Britain. In attaching the 

 marks to the names of species, as components of the 



