186 BRITISH BOTANY. 



which probably will not be applicable to any more than the in- 

 dividual from which it was drawn up. The via-media principle 

 will not remove the difficulty. A compromise between those 

 who think that there are only four species of British fruticose 

 Rubi and those that think there are forty, is impossible. This is 

 one of the genera in which distinctive and comprehensive specific 

 characters have not yet been discovered. A good definition should 

 be both inclusive and exclusive ; it should be the means of com- 

 bination and separation. If the specific characters of the Rubi 

 had both or only one of these characteristics, the opinions of 

 authors Avould be less fluctuating. At present no one can afiirm, 

 on authority, that we have twenty or forty or fifty species of 

 Rubi. The number of synonyms is consequently a great burden 

 upon the student of the species, whether they be genuine or only 

 book-species. The description of the Rubi in this work is not 

 meant to be supplementary to the descriptions of the genus in 

 other works. The so-called species are grouped and described in 

 conformity with the views and descriptions of those who have 

 evidently devoted much labour to this difiicult series of plants ; 

 and the author regrets that the task cannot, for the reasons 

 aforesaid, be performed in a satisfactory manner. It has been 

 above stated, that a carefully drawn-up description of an indi- 

 vidual plant will be a sufficient description of every individual 

 comprehended in the assumed species. The discrepancy of opinions 

 among our leading botanists sufficiently testify that such is not 

 the case in the genus Rubus. It surely is not an unreasonable 

 assumption that every species has a limit ; or, in other words, 

 that every individual of the manifold varieties of a species (this 

 term being employed in a collective or abstract sense) has a 

 stronger resemblance to certain individuals, forming what is 

 called a species, than it has to other individuals, forming what 

 may, for the sake of distinction, be called another species. This 

 limit, it may be inferred, is discoverable by observation, and this 

 may be facilitated by the removal of the plants into places con- 

 venient for their constant inspection, by the cultivation of them 

 both by roots, suckers, and seeds. It is believed that such a 

 limit or definition will never be established by the study of dried 

 plants, nor by the desultory study of living ones. A systematic 

 series of observations, extending over a series of years, will pro- 

 bably have to be begun and vigorously carried on, before we are 



