Inheritance of Mutation in the Common Foxglove. 63 
condition throughout or almost throughout the spike, or they may 
reach the heptandra condition proper which has a petaloid upper 
lip and seven stamens. Heptandrous individuals exhibiting this 
latter condition at the outset often produce eventually a few normal 
flowers. 
6. The distinction between the variety heptandra and the type, 
in all individuals so far observed, is well defined. Where a 
heptandrous individual was found to produce a few normal flowers 
the heptandrous character was always evident throughout the rest 
of the long crowded spike, and conversely, a type plant with a notch 
or slit in a few of the lowest flowers would show a normal structure 
throughout the remaining length of the axis. 
7. There is some indication that the degree of heptandry 
exhibited may be influenced by external conditions, among which 
variations in amount of light and moisture are probably to be 
reckoned. 
8. The variety heptandra behaves to the type as recessive to 
dominant. 
9. Two new forms appeared in the course of the experiments, 
viz., one with stem and leaves nearly smooth, and one in which the 
spots on the lower lip of the corolla had fused to form large blotches. 
The inheritance of these two forms is being investigated. 
The expenses incurred in the course of these experiments have 
been in part defrayed by a grant from the British Association for 
the Advancement of Science, and the use of the garden in which 
they were carried out was kindly permitted rent free by the Botanic 
Garden Syndicate. 
I wish here to express my thanks to Miss D. F. M. Pertz to 
whom I am indebted for the drawings, and to Miss M. Pallis who 
kindly took the photograph. 
EXPLANATION OF PLATE I. 
Illustrating Miss E. R. Saunders’ Paper on Inheritance of a 
Mutation in the Common Foxglove (Digitalis purpurea). 
Photograph showing D. purpurea type and variety heptandra, growing 
side by side in the same bed. Both are in full flower. The heptandrous 
plants show the numerous irregularly diverging stamens which give the spikes 
their characteristic appearance. In some of the flowers of the left-hand group 
the upper lip is becoming petaloid. 
