A Leaf Mutation of the Stayman Winesap Apple

Abstract

A mutation has been observed on a limb of a 'Stayman Winesap' apple tree in the orchard of Pennsylvania State University for more than ten years. This mutation is expressed chiefly in the foliage, although there are indications that the fruit may also be involved. The mutated leaves are very dark green, appearing at times almost black green. They are initially flat, but eventually curl down and back so that the tip of the leaf blade is near the petiole. The foliage gives the branch the appearance of a mass of dark green curls, or of an aphid infection. Matured leaves are stiff and appear thicker than 'Stayman' leaves.