Trans gressive Variability. 433 



Flowers, 5; 101 65 



Species overlap but they will not disappear. And, con- 

 versely, the homogeneity of an unbroken series of forms 

 cannot be taken as established until it can be shown that 

 the forms are grouped round a single center. The exist- 

 ence of two such centers may point to the existence of 

 two distinct types, even though they seem to merge into 

 one another. 



A comparison of the length of the calyx tube in the 

 two forms leads to the same conclusion. The plants all 

 come from the same locality, and the flowers were all 

 plucked from the main stems. 



