RARER FORMS OF RUBUS LATELY FOUND IN DORSET. 73 



Probably, in the lapse of time, many of them will die out, others 

 will remain the species of the future. Our work should be (at 

 least in part) to determine, as far as possible, which forms are 

 likely to survive, and then to group the other forms round them. 



One important point is this : How do the different forms arise 1 

 Have all the individuals now assignable to any given form neces- 

 sarily a. closer genealogical connexion among themselves than with 

 the parent form 1 In other words, may the forms with which we 

 are dealing arise independently at different times and in different 

 places ; or do all the individuals of each form trace back to one 

 common ancestor, the founder of the race 1 If we adopt the latter 

 view, we must be prepared to accept a very high antiquity for 

 many even of our less distinct forms, for in a very large number of 

 instances these forms are common to England and France, to 

 England and Germany, to England and Scandinavia. No doubt, 

 some forms have come to us by immigration from these countries 

 in those long past days when Britain was still a part of continental 

 Europe, and have remained practically unchanged since their 

 arrival. So, I should suppose, has JRubus suberectus come to 

 us from the north, and R. rusticanus (the commonest of all our 

 brambles in southern England) from France. But in many cases I 

 am inclined to think that a similar environment will tend to 

 produce a similar variation, and as bramble forms, even those most 

 nearly allied, seein to be very generally sterile (or nearly so) except 

 among themselves, these variations will tend to become permanent. 

 But they may be quite young forms in one place, very old ones in 

 another. I have thought it well to lay before you these few 

 remarks, because it is most important that you should understand 

 in some degree what the object is which we have before us. It is 

 not to multiply names, nor to burden the human memory with an 

 indefinite number of minute and almost unintelligible distinctions, 

 but step by step to investigate the facts which lie before us, till we 

 reach some explanation of them. Nature is surely doing something 

 in such a case as this which it is well worth our while to study ; 

 but of course we must begin by learning thoroughly to know our 



