hybrid of digitalis. 

 3. Nature of the Hybrid Plants. 



361 



The contents of 14 capsules {gloxiniceflora (Q) x / it tea (rj 1 ) 

 were sown in as many separate pans, and 35 hybrid plants were 

 raised. The mortality among the seedlings derived from the large 

 seeds (about 70 in number) did not seem to exceed the normal 

 mortality which occurs in raising foxgloves from seed, but the 

 numerous seedlings which sprang from the minute seeds (many 

 hundreds) were very weak, and I doubt whether any survived. 



In general appearance the hybrid plants were not intermediate 

 between the two species ; they were much closer to gloxiniceflora 

 than to Intra. 



Leaves. — The ratio of the breadth to the length 



(t 7i — x 1000 1 was determined bv measuring 15 leaves in each 

 Length / 



plant. In 15 female parents (glox.) the mean ratio =272, in 3 



male parents (lutea) =168, and in 27 hybrid offspring =257; thus 



in the relative width of the leaf the hybrid was much nearer to 



gloxiniceflora than to Intra (PI. IV, fig. 2). 



The hybrid plants exhibited a greater vigour than that of the 

 parent species. The leaves tended to be smoother and much more 

 shiny than in gloxiniceflora, and the margin was much more 

 obviously indentated than in either species. The leaves were often 

 considerably thinner dorso-ventrally than in either gloxiniceflora or 

 in Intra, and in plucked leaves the rate of the transpiration of 

 water-vapour was much greater than in gloxinia-flora . The rate 

 was much nearer the normal lutea rate than the gloxinia-flora rate. 



Flowers.— In general aspect the flowers of the hybrids were 

 closer to those of gloxiniceflora than to those of Intra. In each 

 plant the four lowest flowers were measured, and the mean was 

 taken as representative of that plant. The following characters 

 were determined : intensity of purple colouration, percentage spot- 

 ting of lower lip, length of flower, breadth, and the ratio of these 

 two dimensions. The means are given in the following table:- — 



With reference to colour, in the case of one cross the 

 gloxiniceflora parent had white flowers, there being no general 

 purple colouration on the corolla, but the hybrid offspring was 

 nevertheless distinctly purple, the intensity of colouration being 

 determined as 16. Now, at a casual glance the flowers of the 



