Descendants of hybrids usually revert to either one or the other parent or break up in all directions. A cross of the eastern black walnut (Juglans nigra) with the California nut (J. californica) yields a hybrid which is a very great grower. From the seed of this tree a surprising variety of mutations are developed, not only resembling
every possible combination of both parents but numerous strange forms. In fact, among about two thousand seedlings now alive, almost every type or form of walnut foliage may be found. There are startling variations in size, form and number of leaflets, in the size of the plant, in the serration of the margins, in the degree of roughness of the surface, in every feature in which one walnut may differ from another.
