Variation in Color As Well As Leaf Form
These are different examples of Mr. Burbank's curiously crested "wild geranium"-a plant that has been so modified as to merit botanical classification as a fixed variety. It will be seen that there is marked variation in color as well as form. By selective breeding, the color variations might be fixed just as the corrugated condition of the leaf has been. The modification shown has been effected by selective breeding alone, without hybridization.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 9 Chapter 1