White and Yellow Callas
A glance shows the close resemblance in form between the white Calla and its yellow cousin. As might be expected, Mr. Burbank has been able to hybridize the different Callas, producing interesting new varieties. Some of Mr. Burbank's new Callas are of gigantic size, whereas others bear flowers only an inch and a half across.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 2 Chapter 3