74 P- Keeble, Miss C. Pellew and W. N Jones. 
viz., the breaking down of localised groups of chromatophores : at 
all events yellow spots often turn brown as the flower bearing them 
grows older. Further, it is to be noted that, so far as we know, no 
flower which has a magenta ground-colour is devoid of red spots. 
The distribution of red and brown spots in the generation 
produced by selfing plant A is noteworthy. 
The numerical ratio is 17 red-spotted to 5 yellow-brown 
(approximately 3 : 1). The red spots, however, are confined to the 
flowers with magenta ground colour, the brown to the white flowers. 
We have ample evidence (plants D and F) that white flowers may 
exist with red spots. But in such cases the whites are dominant 
whites, and we have no evidence at present of a flower of a recessive 
white bearing red spots. 
The behaviour of the red and yellow-brown spots appears to 
admit of a simple interpretation. 
Reference to Table I. shows that red spots occur only in plants 
containing M. In the case of plant A, the presence of this magenta 
colour factor M is evident from inspection, since the flowers are 
purple. In plants D and F, however, the presence of the factor M is 
not directly apparent, on account of the inhibiting influence of the 
dominant-white factor (W), but becomes evident in the F 1 seifs and 
crosses. Also the plant (E), in which the factor M is absent, has 
yellow-brown spots. From these facts it would appear probable 
that the red colour of the spots is caused by the presence of the 
same factor (M) that is responsible for the magenta ground-colour 
of the corolla, and that the red spots are due to local action of 
magenta colour factor on the yellow-brown spot areas. If this is 
so, it follows that (W) the dominant white factor, which inhibits the 
expression of magenta ground-colour (M), is without this inhibiting 
effect on the M factor in the spot areas. Accepting this interpre¬ 
tation it follows that all white Foxgloves with red spots are dominant 
whites, i.e., carry both W and M, also that, of white foxgloves with 
yellow-brown spots, all are pure recessives with respect to magenta, 
though some may be carrying a dominant white factor. The 
various theoretically possible constitutions of white Foxgloves are, 
therefore :— 
White with red spots—WW MM, WW Mm, Ww MM, Ww Mm. 
White with yellow-brown spots—ww mm, Ww mm, WW mm. 
The ratios obtained by selfing and crossing which support 
these conclusions with respect to the nature of red and yellow- 
brown spots are as follows :— 
