1913-14.] BOTANICAL SOCIETY OF EDINBURGH 299 



curvature, while in the other the angle was diminished. 

 The peduncle of the former, in its natural position on the 

 plant, was inclined at an angle of 60°. It was fixed verti- 

 cally and the corolla tube unbent upwards through 25° — 

 from 110° to 135°. In the latter the peduncle was fixed 

 horizontal, the corolla upwards. The angle of curvature 

 decreased from 120° to 40°. 



From the above experiments it appears that gravity alone 

 is unable to induce curvature, but that gravity and light 

 combined may exercise a directive effect, within limits, on 

 curvature already begun. 



To summarise, the most remarkable points in this sport 

 are : — 



1. The phyllody and chorisepaly of the calyx. The 

 former is not an uncommon occurrence, and has been 

 frequently recorded. 



2. Diatropism and zygomorphy of the corolla. The 

 transition from radial to zygomorphic symmetry is held to 

 be the result of a long period of evolution. Here, in the 

 ephemeral lifetime of: a single flower, the process is 

 initiated and completed. The curvature, it is concluded, 

 is either due to some stimulus, undetected but present in 

 the flower, and is therefore pathological, or it is simply a 

 variation. It will be of interest to observe the develop- 

 ment of the flowers next spring, and the behaviour of the 

 seedlings, should any seeds mature. 



