The Balloon Flower
The upper specimen shows the form of the flower Just before opening, from which the name is derived. It will be seen that the balloon-shape entirely disappears when the blossom has opened, as in the lower figure. This specimen shows the single row of petals characterizing the variety with which Mr. Burbank's experiments began.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 10 Chapter 1