Page:Popular Science Monthly Volume 69.djvu/375

Rh photograph is introduced to give the reader some idea of the work necessary to produce a satisfactory new race of berries. "Of the 40,000 blackberry X raspberry hybrids of this kind 'Phenomenal' is the only one now in existence. From the other 25,000 hybrids, two dozen bushes were reserved for further trial."

An astonishing result of the hybridization between the black walnut. Juglans nigra, used as the pistillate parent, and the California walnut, J. californica, staminate parent, are walnut trees which grow with such an amazing vigor and rapidity that they increase in size at least twice as fast as the combined growth of both parents. Many tremendous growers are got in the first generation, but in the second there are included

some of the most rapidly growing trees, perhaps, in the world. This hybrid has clean-cut, glossy bright green leaves from two to three feet long with a sweet odor like that of apples, but it produces few nuts. Curiously enough the result of hybridization by using the pollen of nigra on pistils of californica produces in abundance large nuts of a quality superior to that possessed by either parent.

The famous Shasta daisy is the result of a multiple crossing between an American and a European species of field daisy and then between these hybrids and a Japanese form. The fragrant calla, known as 'Fragrance' is descended from a single individual found by Burbank while critically examining a block of Little Gem calla seedlings. He was surprised in this examination by a fragrance resembling that of violets or water-lilies; as be had long been seeking a fragrant calla,