The Stem of the Russian Barberry
The barberry is well known to be a very thorny plant, but the Russian species is peculiarly well armed, as this picture testifies. Now that thornless blackberries are in evidence, the plant-developer will be expected to remove the thorns from the barberry at the same time that he improves its fruit.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 6 Chapter 8