PREFACE. Vll 



one, two, or as some think four species. Such an opinion 

 is the natural result of an examination of a few specimens, 

 perhaps not very perfect, preserved in an Herbarium. But 

 if much study of the plants in their native places of growth 

 is combined with that of an extensive series of preserved 

 specimens of each form, it does seem to me that nature pos- 

 sesses many more species than those distinguished men are 

 prepared to admit. It is quite likely that the time may 

 come when several of the forms here looked upon as species 

 will be shewn not to be distinct from others. The many 

 blunders which have been made by myself and other students 

 of this difficult genus would make it very presumptuous in 

 me to think otherwise. Dr Godron in his valuable essay Le 

 genre Ruhua consider e cm jmint de vue de Vespece, {Mem. de 

 la Societe R. de Nancy ^ 1849, p. 210), has t^liewn con- 

 clusively that w^e cannot reduce all the European Ruhi to 

 the species described by Linnaeus, and proved that there are 

 real and constant characters by which to distinguish as true 

 species many more than were known to the great Swedish 

 botanist. 



As a contrast to the idea that the number of species is 

 small, it may be mentioned that a German botanist, (P. J. 

 Miiller) has published (16 and 17 Jahresherichte der Polli- 

 chia) descriptions of what are supposed by him to be 236 

 species of Rubi inhabiting France and Germany. I believe 

 these to be descriptions of mere forms. They might have 

 been of considei*able value had theu' author more frequently 

 identified his plants with those of other botanists, or pointed 

 oiit their distinctions from them : also, if he had given 



