Stages of Sunflower Progress
These pictures illustrate the stages of development of Mr. Burbank's Russian-American sunflower hybrid. It will be seen that the petals or rayflowers gradually invaded the seed-head from circumference toward the center, until finally they completely won the day. In its final stages, the transformed flower bears scant resemblance to its parent.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 8 Chapter 3