Foliage and Fruit of the Royal Walnut
The foliage of the eastern and western black walnuts is very similar, and the foliage of the Royal hybrids may be said to bear close resemblance to that of both parents. It is grown in extreme profusion, however, as this picture shows, in keeping with the very great vigor and fecundity of the tree.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 11 Chapter 7