Ixxxii CHARLES CARDALE BABINGTON. 



of the Euhi to be found in Britain. I have therefore named and 

 described many forms which seem to be well marked, but may not 

 prove to be permanent after the requisite study has been bestowed 

 upon them in their native places of growth. 



Focke justly remarks that "Very few botanists recognize the 

 fact that there are in Europe at the present time perhaps fifty 

 times more apparently permanent forms of plants reproduced 

 from seed, than we find species recorded in books. According to 

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

 as a decided criterion of species." — 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." — Focke, 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 is 

 far from having 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 Belgique (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 

 unnatural ; 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 shew 

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



