Page:Popular Science Monthly Volume 66.djvu/228

224 burr is originally intended to keep off the birds. In developing a superior variety of the Persian (often called English) walnut (Juglans regia), the shell was made too thin, so that the birds could break in. It was necessary to make new selections and crossings to thicken the shell and still retain its other superior qualities.

The Pierce grape was a bud sport from the Isabella, producing much larger fruit. This bud sport remains constant. All the seedlings even from it are similar to the Pierce grape, following the bud sport (Pierce) and not reverting to the real parent form of the Isabella. Some ripen early, some late; some are pale, and some are black; but all resemble the Pierce more than the Isabella. Cultivating a choke cherry, the seeds all from one parent tree, many variations are found, although the soil in which they are placed is uniform. Among them was found one variant less bitter than usual; others earlier or later ripening and with larger or smaller fruit or leaves, and an almost bewildering number and variety of other variations. A peach-almond cross often develops a tree as large as ten peach trees or almond trees of the same age. Sometimes a similar cross with different individuals of the same species will produce opposite or totally different results, owing to past heredity, either recent or far back. Crosses are sometimes more vigorous than either parent and more than any descendant, but other cases are just the reverse. The more variant crosses are often less vigorous, and sometimes yield seedlings that can not exist. Sometimes all die in the fruiting season. A peach named 'Quality' is one of the best peaches extant—a cross of the Muir and the Crawford. A cross of the nectrine and peach also produces variant types of value. In some hybrids of petunia and tobacco, the roots fail while the tops may be of unusual vigor. These individuals can only be kept alive for any length of time by grafting, another instance—if other were needed—of the parallelism of crossing and grafting.

"A character may be latent through many generations or centuries,