Volume II JUNE, 1912 No. 2 



SPECIES HYBRIDS OF DIGITALIS. 



By W. NEILSON JONES, M.A., MEW ; 



University College, Reading. 60TAN' 



Historical. 



Hybrids between the various species of Digitalis have been recorded 

 from time to time and in many cases can be produced without difficulty 

 or even occur in nature. A general summary of the literature up to 

 1881 is given by Focke in Die Pflanzen-Mischlinge. The hybrids most 

 frequently recorded are those between D. purpurea and D. lutea, and 

 between D. purpurea and D. 'grandiJlora\ the accounts being somewhat 

 contradictory. 



The cross between D. purpurea and D. lutea has been re-investigated 

 by J. H. Wilson and described in the Report of the 3rd International 

 Conference on Genetics (1906). Briefly, the facts concerning the 

 hybridising of these two species are as follows : 



It was found much easier to effect the cross when D. purpurea was 

 l^ used as pollen parent. The reciprocal crosses differed from one another 

 as to their flowers, in each case more closely resembling the seed-parent. 

 The hybrid having D. jmrpurea as seed-parent had larger and wider 

 flowers of a rose colour although the D. purpurea used was a white 

 flowered variety without coloured spots (from which it was concluded, 

 incidentally, that colour may be latent in a white foxglove). In the 

 cross in which D. lutea was used as seed-parent the flowers were 

 narrower and in colour creamy-yellow or almost white with a pale rose 

 flush, even when a purple D. purpurea was used. The flowers of both 

 hybrids had purple spots inside the corolla tube. 



In a subsequent series of experiments Wilson found that the F^ 

 plants of both hybrids varied considerably among themselves as to 

 flower colour. This was possibly due to the use of an impure strain. 



The reciprocals were indistinguishable until they flowered. 



No fertile seed was obtained from either hybrid. 



' D. grandiftora L. is synonymous with D. ambigua Mur. 

 Journ. of Gen. ii 6 



'?V 



