Cockayne. — Ecological Studies in Evolution . 



11 



11. Rubus Barkeri Cockayne. 



This is a presumably non-flowering species (see Cockayne, 1910, p. 325) ; 

 at any rate, cuttings from an adult plant growing luxuriantly and under 

 most varied conditions for a period of thirteen years have never flowered. 

 Be this as it may, the plant in question, although closely related to R. parvus 

 Buchanan, differs from that species in its trifoliate leaves with lanceolate* 

 leaflets and not simple linear leaves, its serrate and not dentate leaf-margins, 

 its different autumnal colouring and its greater size in all parts (see fig. 1). 



Fig. 1. — Outline of Leaf of (a) Rubus Barkeri, (b) R. parvus, x f. 



'Only one plant was originally noted. Recently I have seen abundance of 

 Rubus parvus in various localities in Westland and under different condi- 

 tions, but it is remarkably constant in characters, and presented no transi- 

 tions towards R. Barkeri. I know well that my action in " creating " a 

 taxonomic species in this case is open to adverse criticism, especially as 

 I believe that the original wild plant may be the only one in existence ; but 

 if a species can originate by mutation there must be a time when there is 

 only one individual, and if so, and its characteristic marks are of " specific " 

 importance, it is just as much a " species " as if there were thousands of 

 similar individuals. 



* So defined in original description, but leaflets in fig. 1 are broader. 



