INHERITANCE IN THE FOXGLOVE, AND THE RESULT 
OF SELECTIVE BREEDING. 
By ERNEST WARREN, D.Sc. Lond. 
In Bioiiietnku,Yo\. xi. pp. 302 — 327, 1917, the authoi- published a preliminary 
report on the earlier results obtained in the breeding of foxgloves ; and the present 
paper contains some account of the final results of the selection experiments. 
In 1914 ten foxglove plants {Digitalis gloxiniaejiora), obtained from various 
sources and of different characteristics, were crossed among themselves and also 
self-fertilised. In subsequent years, 1915 — 19, new generations were obtained 
chiefly by the self-fertilisation of selected parents. The measurement, or when 
not possible the grading, of certain characters (pelorism, colour, size of flower, 
spotting of flower, etc.) was undertaken in all the generations in order to deter- 
mine the effect of selection when selfing alone occurred in an apparently pure 
race. 
1. Pelorism. 
Mendelian inheritance occurred in a typical fashion. A peloric plant crossed 
with a non-peloric plant produced non-peloric offspring. On selfing these, or 
crossing them together, there resulted on the average one peloric to three non- 
pelorics. 
Of the 1 0 parent plants two exhibited the peloric condition in a fully developed 
form, and the rest were non-peloric. The character was very perfectly recessive, 
and by breeding, it was found that three of the remaining plants were really 
heterozygous, while all the others were non-peloric and homozygous. 
It was soon observed that the peloric condition was by no means a clearly 
defined and fixed character. Pelorism in the foxglove may be regarded as an 
abnormal lack of power to produce internodes between the flower-buds, and con- 
sequently there may result considerable fusion of such buds with one another. 
The maximum stage of pelorism is seen when the main-axis is short and 
abruptly ceases to grow in height. Only two or three normal flowers may be 
produced by the axis, and its blunt, sharply truncated end is surrounded by a 
whorl of bracts or sepals, petals being absent. Sometimes a ring of sessile anthers 
occurs (PI. I, figs. I, ll). 
In typical pelorism the inability to produce internodes aifects the terminal 
portions of all of the flower-axes of a plant, both central and side-axes. A variable 
number of flower-buds fuse and the corollas unite and may form a large sym- 
metrical cup or saucer of some ornamental value, but the sepals mostly remain 
