Some Cactus Seedlings-2
After making his first selection from the "flats," Mr. Burbank transplants his seedlings in the ground, as shown. From the time the seedling first shows its head until the final object is achieved, there Is selection, selection, constant selection. The points for which he watches in his process of selection are clearly explained in the treatment of each specific subject.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 1 Chapter 6