TACCTXIUM IXTERMEDTUM 259 



VACCINIUM INTERMEDIUM IIutiie. 

 Br W. Balfour Gourlat, M.B., and G. M. Veters, M.R.C.S. 



This natural hybrid between Vaccinium Myrtilhis and V. Vitis- 

 idcea was discovered in Britain by Robert Garner in Maer Woods, 

 Staffordshire, and was exhibited by him at the meeting of the 

 Linnean Society on March 7, 1872, when " the general opinion 

 elicited hj their examination was that they were a luxuriant state of 

 V. Vitis-icl(Ba, due to situation, rather than a hybrid " (see Journ. 

 Bot. 1872, 122). It was fully described by Mr. N. E. Brown in 

 Journ. Linn. Soc. xxiv. 125 (1887) as V. intermedium Ruthe, from 

 specimens collected by T. G. Bonney in August 1886 on Cannock 

 Chase ; in a postscript to the paper, which is accompanied by an 

 excellent plate, these are identified with Garner's specimens exhilDited 

 at the Linnean Society. Since then little notice seems to have been 

 taken of the plant, but several rather interesting points and questions 

 arise when one examines its habit and distribution. 



In the first place it is locally very abundant in the Cannock Chase 

 area of Staffordshire — we have found it in a score of distinct 

 and widely-separate locaHties. Slight variations in plants from the 

 different localities and their wide separation suggest different acts of 

 hybridization for each locality. The onl}^ other place in Britain 

 from which it has been recorded is Caithness. This is rather remark- 

 able, for one would think that there must be many other localities 

 where the parent species grow together and hybridization might take 

 place ; none, however, have been recorded, and it seems unlikely that 

 the jjlant occurs and has been overlooked in such areas, as the upland 

 regions of Britain have been carefull}^ botanized. 



The question arises, Can any circumstance at Cannock Chase be 

 specially favourable for the production or spread of the h^^brid ? 

 The answer to this seems to be : Human interference. 



In all but three localities in which the plant was found there was 

 indisputable evidence of man's handiwork. Cannock Chase during 

 the last five years, and for many years before to a lesser degree, has 

 been a military ti-aining-area, and many roads, trenches, gun-pits, and 

 drains have been constructed ; and it was in such localities that the 

 hybrid was found. Moreover, where the work of man is recent the 

 patch is small and vice versa, e. g., patches one yard square were 

 found in conjunction with work obviously done since the beginning of 

 the War, whereas one large patch of an acre in extent had its focus 

 in an artificial bank on which birch-trees of considerable size were 

 growing, proving it to be some twenty years old. Each patch spreads 

 vegetatively by creeping rootstock.s. In unmolested areas Bilberry 

 and Cowberry grow intermingled, but in such areas the hybrid is 

 conspicuous by its absence. It would be interesting to know if the 

 Caithness locality gives similar evidence of human interference. 



It may be noted that V. Myrtillus flowers earlier than V. Vitis- 

 idcea, though some overlapping usually occurs. The hybrid resembles 

 the latter in the cylindrical stem and evergreen and rather coriaceous 

 leaf, but favours the former in having awned anthers and in the shape 



