PEEFAOE. Xlll 



having less reference to the British Flora* Here again it should 

 be added that, in deciding upon the admission or rejection of 

 particular species, great use has been made of the arguments and 

 conclusions of Hewett Watson, as well as of the detailed review 

 of them contained in the ' Geographic Botanique ' of Alphonse 

 de Candolle. 



Taking into account the omission of all plants erroneously in- 

 dicated as British, it wUl still, no doubt, be a matter of astonishment 

 that, whilst the last edition of Hooker and Arnott's Flora contains 

 1571 species, and that of Babiagton's ' Manual ' as many as 1708, 

 (exclusive of Cliara), that number is in the present Work reduced to 

 1285. This is not owing to any real difference of opinion as to the 

 richness and diversity of our vegetable productions, but is occa- 

 sioned by a different appreciation of the value of the species them- 

 selves. The Author has long been persuaded that the views origi- 

 nally entertained by Linnaeus of what really constitutes a species, 

 were far more correct than the more limited sense to which many 

 modern botanists seem inclined to restrict the term ; and that in 

 most cases where that great master had good means of observation, 

 he succeeded admirably in the practical application of his principles. 

 At any rate, if those minute distinctions by which the innumerable 

 varieties of Brambles, of Roses, of Hawkweeds, or of Willows have 

 of late years been characterized, are really more constant and more 

 important than the Author's experience has led him to conclude, they 

 cannot be understood without a more complete acquaintance with 

 trifling, vague, and sometimes theoretical characters, than he has 

 himself been able to attain, or than can ever be expected from the 

 mere amateur. It is considered, therefore, that such details would 

 be out of place in the present Work, and those who feel sufficient 

 interest in the subject to devote their leisure hours to the investiga- 

 tion, can only hope to master it by a close and patient study of the 

 numerous, often very carefully elaborated Monographs pubHshed 

 in Germany, Sweden, and France, as well as in this country. ' The 

 species are here limited according to what are conceived to have 

 been the original principles of Linnaeus ; and the Author, in sub- 

 mitting his views to the judgment of the scientific world, trusts that 

 they will not be attributed to hasty generalizations or conjectural 



• The species mentioned as sontli European generally penetrate more or less into 

 northern Africa ; those which are said to extend eastward to the Caucasus often spread 

 more or less over Persia, and further into central Asia, 



I 



t-^\ 



