Prunes Drying on the Tree
A plum that has a sugar content sufficently high to cause it to dry without decaying is legitimately called a prune. The one here shown appears to have that characteristic. But there is another quality which a good commercial prune must have-it must drop from the tree when ripe. So the clinging propensity of the prunes here shown is a fault thatbars this particular variety from popularity.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 5 Chapter 3