60 Wilson. — Observations on Epigcea repens, L. . 



dioecism is of a later development than polymorphism, it is 

 still of no very recent date. 



The corollas of the female forms are as a rule from one-third 

 to one-seventh smaller than those of the male. Figs. 9 and 

 10 show an average female and an average male flower drawn 

 in relative proportions. 



The throat is somewhat more open in the female than in 

 the male form. In color, too, the smaller pistillate flowers 

 seem to have gained an advantage over the staminate form, 

 the latter often having little or no color, while the former 

 develops beautiful shades of pink or rose color. It is not 

 strange that the smaller and less showy female flowers should 

 acquire a deeper hue than the larger male flowers in order to 

 be equally conspicuous and attractive to the insects which 

 must carry the pollen from one to the other if the seeds are 

 to be formed. 



The whole male plant, under most conditions of growth, 

 presents a decided appearance of vigor which does not seem 

 to belong to the female. In the male there is less color the 

 flowers often being white, the leaves are larger, the vegetating 

 shoots are longer and more thrifty ; while in the female the 

 color is brighter and deeper, the leaves are considerably 

 smaller and the creeping branches much shorter. The male 

 plant often looks thrifty in localities where the female looks 

 dwarfed. 



In examining Epig&a in different localities this year the 

 writer has in several cases made a careful numerical estimate 

 of the ratio of the sexes, to each other. The results obtained, 

 although necessarily rather indefinite on account of varying 

 conditions that are difficult to estimate, may be of interest to 

 some, as touching on the question of development and per- 

 sistence of sex. 



Quite a number of observations and investigations made on 

 animals seem to show that where the struggle to maintain 

 life is a hard one, a preponderance of males are produced ; 

 while on the contrary, when food is abundant and there is no 

 struggle, females predominate. The very few observations 



