[Vol. 2. 1915] 



274 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



these would unquestionably be designated as of a retrogres- 

 sive character, such, for example, as the defection of a part of 

 the color pattern of the corolla; others, such as the accentuated 

 incision of the leaves and corollas and the development of the 

 venation, as progressive alterations ; while still others may not 

 with any substantial reason be assigned to either class. With 

 reference to taxonomic criteria, it may be said that the di- 

 vergent individuals are distinguishable at sight from the 

 parental stock, but the real test of the characters presented 

 is not their degree or kind of departure, but their stability and 

 permanence indicative of actual modifications of the germ- 

 plasm. 



