One of the First Stoneless Plums
This fruit represents partial success in the development of the stoneless plum. It resembles the original French Sans Noyau, its parent, in shape and general appearance, but is much larger and has an excellent flavor. It lacks some essentials, however, but was of service as a parent in further crossbreeding experiments that might lead to ultimate success.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 5 Chapter 5