PREFACE. Vll 



named which will assist them in their studies. Koch's 

 Synopsis filorce Germanicce, ed. 2, and Grenier and Godron's 

 Flore de France are strongly recommended, also, although 

 in a rather less degree, Lloyd's Flore de ? Quest de la France, 

 Brebisson's Flore de la Normandie, and Cosson and Ger- 

 main's Plore des environs de Paris, ed. 2. Boreau's Flore 

 du Centre de la France, ed. 3, and the scattered papers of 

 M. Alexis Jordan of Lyons are valuable for the study of 

 varieties ; for many of their species can claim no higher 

 rank. But, above all, the works of Fries deserve careful 

 study especially his Novitice Florce Suecicw, with its three 

 Mantissas, and Summa Vegetabilium Scandinavia?. It is 

 necessary to warn students against the very common error 

 of supposing that they have found one of the plants de- 

 scribed in a foreign Flora when in reality they have only 

 gathered a variety of some well-known British plant. The 

 risk of falling into such errors renders it necessary to con- 

 sult such works as those of Messrs. Borean and Jordan with 

 great caution, lest we should be misled by descriptions, most 

 accurate, indeed, hut often rather those of individuals than 

 species. Amongst plants so closely allied as are many 

 of those called species in some continental works, it is 

 scarcely possible to arrive at a certain conclusion without 

 the inspection of authentic specimens. 



The Author takes this opportunity of returning most 

 sincere thanks to his botanical friends and correspondents 

 (far too numerous to record by name) for the great assist- 

 ance they have again rendered to him by the communica- 

 tion of valuable suggestions, observations, and specimens. 



The book has been again carefully revised throughout, 

 so as, if possible, to keep pace with the rapidly advancing 

 knowledge of British plants. 



As many as possible of the real English names are given. 

 All the genera and species could not be thus named, owing 



