262 Noii-Isolablc Races. 



previous summer. T have a record, which has been al- 

 ready alluded to, of the number of petals of all the 

 flowers of each of the plants of 1892 ; these were recorded 

 in the same way in 1893. But I only give here the mean 

 numbers of petals per flower. 



MEAN NUMBER OF 

 PETALS PER 



1892 



11 



9 

 10 



8 

 10 



9 



The anomaly was thus diminished on every single 

 ])lant as the result of transplanting to dry earth. 



The results of all these experiments prove that the 

 production of more than five petals in a flower is inde- 

 pendent of the position of this flower on the plant, but 

 on the other hand is dependent in a high degree on the 

 external conditions under which the particular flower 

 passes its early stages, i. e., the most susceptible period 

 of its existence. The number of petals varies directly 

 with the vigor of the ])lant, the moisture and richness 

 of the soil, the warmness of the weather and even the 

 amount of sunshine during this suscepti1)le period. 



Cultivation in the garden is therefore bound to con- 

 vert the steep half curve of the wild locality (Fig. 51 

 for 1887) into a flatter one which will gradually extend 

 to higher numbers of petals and will ultimately develop 

 a new apex. 



This process, however, takes place more conveniently 

 and more certainly, if the cultivation is combined with 

 selection (see the same figure). The latter process picks 



