THE RELATIONSHIP OF VARIATION TO 



ENVIRONMENT IN CHRYSANTHEMUM 



LEUCANTHEMUW 



(Abstract) 



It is not sufficient to show that a particular species 

 possesses a certain index of variabiUty in a restricted 

 locahty. We must attempt to ascertain the component 

 stimuli forming the environment and learn the effect 

 which each group of stimuli has on the variability of the 

 organism in question. Only by so doing can we draw 

 accurate conclusions concerning the factors of evolution. 



While natural environment does not furnish us with 

 the best conditions for the solution of the problem, a 

 study of the variability exhibited by two groups of 

 Chrysanthemum leucanthevtuTn (the common white 

 daisy) has brought to light some facts of considerable 

 interest. 



In a comparison of two groups of 500 each, obtained on 

 the same day from localities less than a mile apart, it was 

 found that the group having the greater nourishment had 

 the greater variability as measured by the "index of vari- 

 ability." 



the "average deviation" 



(^) ^ ^ 



and the amplitude or range of variation. Thus the data 

 obtained in this particular study suggest that the differ- 

 ence in variability is dependent on food supply, or, in 

 other words, that chemical stimuli are one of the under- 

 lying factors producing variability. This is a conclusion 



•Reprinted from The Ohio Naturalist, vol. 4 (1904), p, 56. 



