Balloon Berry Bush After Pollenation
Here small paper bags have been tied loosely over the flowers that have been cross-fertilized. Mr. Burbank does not usually find it necessary to resort to this expedient, for if the stigma of a flower is entirely covered with pollen, there is little danger of subsequent contamination with other pollen. To make assurance doubly sure, however the paper bags may be used, particularly by the amateur who operates on a small scale.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 3 Chapter 3