ON THE OCCURRENCE, BEHAVIOUR AND ORIGIN 

 OF A SMOOTH-STEMMED FORM OF THE COM- 

 MON FOXGLOVE {DIGITALIS PURPUREA). 



By EDITH R. SAUNDERS, 



Lecturer, late Fellow, Newnham College, Cambridge. 



In the course of an earlier investigation on the inheritance of the 

 peculiar modification of the flower known as heptandry, which is occa- 

 sionally met with in Digitalis purpurea, it was incidentally noted that 

 some individuals exhibited a distinct variation from the recognised type 

 as regards surface character^ The typical plant is generally described 

 as having all the aerial green parts covered with hairs, those on the stem 

 and petioles being so abundant as to give these structures a downy, 

 grey appearance. In the particular individuals in question, on the other 

 hand, the vegetative region of the stem was conspicuously green, smooth 

 and shining, and the leaves were distinctly less hairy on the upper sur- 

 face and deeper green in colour, so that the eye was at once attracted to 

 these plants. The data obtained in regard to this partially glabrous 

 condition pointed to its relation to the completely hairy state being that 

 of dominant to recessive, but the records were neither large enough nor 

 derived from a sufficient number of generations to furnish conclusive 

 evidence on this point, nor did they serve to show whether or not this 

 character is constant and breeds true. In order to obtain decisive proof 

 as to the behaviour of this form the experiments were continued through 

 several further generations. In passing it is worth mention that a 

 further object of the investigation was to ascertain whether the two 

 distinct abnormalities, peloria and heptandry, exhibited any phenomenon 

 of the nature of linkage, or whether each recessive character was inherited 

 without relation to the other. The later work showed that these two 

 modifications are, in fact, inherited quite independently and that in 

 ^ The New Phytologist, Vol. x. 1911, p. 60. 



