Striped Flowers 335 



the other half singles, the question arises, 

 where are the singles and the doubles to be 

 found on the parent-plant? 



The answer is partly given by the following 

 experiment. Starting from the general rule of 

 the great influence of nutrition on variability, 

 it may be assumed that those seeds will give 

 most doubles, that are best fed. Now it is man- 

 ifest that the stem and larger branches are in 

 a better condition than the smaller twigs, and 

 that likewise the first fruits have better chances 

 than the ones formed later. Even in the same 

 pod the uppermost seeds will be in a compara- 

 tively disadvantageous position. This concep- 

 tion leads to an experiment which is the basis 

 of a practical method much used in France in 

 order to get a higher percentage of seeds of 

 double-flowering plants. 



This method consists in cutting off, in the first 

 place the upper parts of all the larger spikes, in 

 the second place, the upper third part of each 

 pod, and lastly all the small and weak twigs. 

 In doing so the percentage is claimed to go up 

 to 67-70;^, and in some instances even higher. 

 This operation is to be performed as soon as the 

 required number of flowers have ceased blos- 

 soming. All the nutrient materials, destined 

 for the seeds, are now forced to flow into these 

 relatively few embryos, and it is clear that 



