A New Thornless Fruit
Mr. Burbank's thornless blackberry is well known, and now, by the application of the same methods, he has produced his first thornless raspberry. Plants which are under cultivation no longer have need for thorns and it is possible to save them the extravagance of producing them so that they may have more energy to put into their useful product.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 1 Chapter 8