PKOFESSOR BAIilNGTON ON KUJiUS IN 181)1. 287 



my view, it is therefore erroneous to take permanency from seed as 

 a decided criterion of species." — Foclcc, pp. 89, 90. He also justly 

 remarks that "it is only by means of minute descriptions that we 

 are able to recognize with certainty the various forms of plants. 

 Those who rely too much on single characters for the recognition 

 of species in very short diagnoses or tabular forms will only too 

 often find themselves in a maze of error, for there is not one single 

 character that can be considered as absolutely permanent and 

 reliable." — Fockc, p. 91. 



Introductory. 



After much consideration I have arrived at the conclusion that 

 Dr. Focke's arrangement is more satisfactory than that of Genevier, 

 for it does not separate allied plants so much. Genevier seems to 

 have wished to use an artificial arrangement, which he probably 

 believed to be more convenient for the readers of his book, than a 

 more natural one. Although he has to some extent succeeded, he 

 has far from wholly done so. I have therefore chiefly followed 

 Focke in this essay; merely deviating from him in those cases 

 where our views do not quite agree. 



M. Camus, in his recently published Catalogue des plantes de 

 France, de Suisse, et de Bchjique (1888), has made a bold attempt, with 

 some success, to form what may be called aggregate species. I fear 

 that we can only approach to the formation of such definite and 

 natural collections of named forms at present. I have endeavoured 

 so to arrange our forms, as far as they are yet determined, for there 

 may probably be many more than we know at present, in as con- 

 venient and at the same time natural a manner as is in my power. 

 It will be seen that the present arrangement is fundamentally the 

 same as I have always followed, although it will be new to our 

 botanists in some few points. I do not see how to improve it. It must 

 be always remembered that a linear arrangement is necessarily un- 

 natural ; for the affinities of the different plants do not lie in only 

 two, but in many directions. We must therefore not be surprised 

 by finding plants, which are manifestly allied, placed in distinct 

 groups, when they seem, taking all the characters into account, to 

 be more fitly there placed than with the others to which they show 

 a relationship. Of course this adds much to the difficulty of ar- 

 ranging them upon anything approaching to a natural system; but 

 we are obliged to employ a linear arrangement. 



Gaudoger, in his remarkable Flora FAiropcea, tom. viii., divides 

 the genus into three, and has taken much pains to reduce the 

 number of species by arranging under each of his species those of 

 other authors which he combines with them severally. To this 

 attempt I have paid much attention, but have not thought it 

 desirable to adopt the new genera into which he divides liubiis. 

 Unfortunately he gives no definition of these genera, nor of the 

 species, although he points out innumerable varieties under each of 

 the latter. 



As Dr. Focke remarks, there seems to be endless variation 

 amongst brambles, and therefore endless forms which may and 

 perhaps ought to be named and defined. It matters little whether 



