PREFACE. 



In this work it has been the Author's wish to adopt in all 

 cases those names which have the claim of priority, unless 

 good cause should be shown for a contrary proceeding ; and 

 with this object he has carefully examined nearly all the 

 best European Floras, comparing our plants with the de- 

 scriptions contained in them, and in most cases with 

 foreign specimens of undoubted authenticity. In the adop- 

 tion of genera and species an endeavour has been made, 

 by the examination of the plants themselves, to determine 

 which are to be regarded as truly distinct, — thus, it is 

 hoped, taking Nature as a guide. Still, let it not be sup- 

 posed that any claim is made to peculiar accuracy, or that 

 the Author considers himself qualified to dictate to any 

 student of botany ; for he is well aware that there are 

 many points upon which persons who have carefully studied 

 the subject form different conclusions from those to which 

 he has been led. 



The progress of our knowledge has caused changes in 

 the nomenclature in successive editions of this book and 

 in the Author's views of the value of forms — as species 

 or varieties. The inconvenience of these alterations to 

 all, especially to statistical botanists, is fully admitted ; but 

 the Author does not know of any mode by which it can 

 be avoided if each edition is to be brought up as completely 

 as is in his power to the contemporary knowledge of our 

 plants. No alterations have been admitted until careful 



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