Contrasting Types of Cactus
At the left, a colony of spineless cactus called the "Tapuna"; at the right a quite different type called the "Tuna." Like all Mr. Burbank's spineless cactuses, these are crossbred seedlings; and they are of closely similar lineage, notwithstanding their widely different appearance. Another instance of the segregation of hereditary characters.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 8 Chapter 7