56 The Ohio Naturalist. [Vol. IV, No. 3, 



THE RELATIONSHIP OF VARIATION TO ENVIRON= 

 MENT IN CHRYSANTHEMUM LEUCANTHEMUM. 



Iv. B. WAI.TON. 



{Adsirad.) 



It is not sufficient to show that a particular species possesses a 

 'Certain index of variabilit}- in a restricted locality. We must 

 attempt to ascertain the component stimuli forming the environ- 

 ment 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 varia- 

 bility exhibited by two groups of ClDysanthoiniiii leucanthemiim 

 (the common white dais}' ) 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 varia- 

 bility as measured by the " index of variability " 



the " average deviation " 



and the amplitude or range of variation. Thus the data obtained 

 in this particular stud}- suggest that the difference in variabilit\- 

 is dependent on food supply, or, in other words, that chemical 

 stimuli are one of the underlying factors producing variability. 

 This is a conclusion that has been previously suggested but not 

 definitely established by statistical methods. 



It is evident that there is a need for further investigation in 

 this direction on animals as well as plants, for only by the careful 

 application of statistical methods can the fundamental principles' 

 .of evolution be ascertained. 

 Kenyon College. 



FURTHER FLORISTIC STUDIES IN WEST VIRGINIA. 



W. A. KEIvI-ERMAN. 



[Abstract.) 



An account of a collecting trip through jiortions of Randol]>li 

 and Webster Counties, especiall}- in the Cheat and Point Mount- 

 ains, with brief outline of the more conspicuous and interesting 

 fungi — several of which are now reported for the first time. 



