The Balloon Berry
An unfamiliar, but promising fruit with which Mr. Burbank has experimented extensively in recent years is the variety of Rubus, called the Balloon Berry, so named because of the shape of the fruit. It may be trained as an upright shrub, and its large white blossoms appear very early in the spring.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 6 Chapter 5