INTRODUCTION xv 



Bonnier, who has bestowed on this subject an enormous 

 amount of research, has published, in the Annales des 

 Sciences Naturelles for 1894, ^^e results of a very large 

 series of experiments on the cultivation, at different alti- 

 tudes, of individuals obtained by the division of a single 

 parent stock, which fully confirm these statements. Pro- 

 fessor Chodat also, of Geneva, has established in the Jura 

 an alpine botanic garden for the observation of similar 

 phenomena. 



It is hoped that, with the present work in his hand, 

 the tourist who is already acquainted with the most 

 familiar English plants will be able to recognise, in the 

 great majority of cases, the plants which he meets with 

 in his alpine wanderings. But he must not expect to 

 be able to do so in all cases. The experienced botanist 

 is often at a loss in distinguishing between two nearly 

 allied species, even with much fuller descriptions before 

 him. The acceptance of the theory of evolution, now 

 all but universal, implies that there may be no hard and 

 fast lines between species, any more than there are 

 between varieties ; that a species is not a sharply defined 

 assemblage of individuals which has existed as such 

 from time immemorial; that varieties, species, genera, 

 tribes, orders, may all pass into one another by insen- 

 sible gradations. There are some genera — among these 

 may be especially mentioned the large families of Brambles, 

 Roses, Hawkweeds, and Willows — in which different autho- 

 rities differ most widely in their interpretation of what 

 constitutes specific difference ; Continental botanists, as a 

 rule, describing a much larger number of species than their 

 English confreres. In these cases special manuals must 

 be consulted. And in other instances, as, for example, in 



