CALIFORNIA BLUE OAK (_Quercus douglasii_) receives its name from the color of its foliage in spring and early summer in the valleys and on the rolling foothills of central California. Later in the summer, when the dry season is on, the leaves lose some of their blue, on account of age, but more from an accumulation of dust; but even then the form of the tree, from its habit of growing in open formation like an old apple orchard, presents an attractive picture. It is often associated with the valley oak, which is larger and more stately, but the blue oak loses nothing by the contrast. It is occasionally called rock oak, but for what reason is not clear. It is known, too, as mountain white oak, or simply white oak, and as blue oak. Its range covers central California from Mendocino to the Mojave desert, and from the immediate coast inland through the valleys to the Sierras, and upward to an altitude of 4,000 feet where the tree degenerates into a shrub which has neither beauty nor utility. The species reaches its best development in the Salinas valley from twenty to sixty miles from the coast. There the largest trees are found, and also some that have assumed peculiar forms. In positions exposed to the never-ceasing sea winds which sweep up the valleys, the blue oaks lie prone like logs, their tops pointing away from the wind. They grew in that unnatural position, having been pressed flat by the wind since they were seedlings. This oak’s ashen gray bark harmonizes well with the dry summer grass and dull sand and gravel which surround it during the hot period. The branches are often covered with green-gray lichens which somewhat modify the aspect of the tree under close inspection. The leaves are irregular in form. Some closely resemble leaves of the eastern white oak, while others are almost or quite without lobes. During the growing season the acorns are deep green, but when approaching maturity they change to a chestnut-brown. They vary in shape as much as the leaves. Some are almost eggshaped, bulging out above the cup which seems too small; but all of them do not assume that form, but may be short and symmetrical, or very long and slender. Woodpeckers store these acorns in large numbers, and they search out peculiar places for their hoards. A knot hole in the weatherboarding of an old barn, granary, or school house is considered ideal, though when the acorns are so disposed of, they are out of reach of the woodpecker forever. Another method is to peck holes just large enough for an acorn in fence posts or dead tree trunks, and hammer the acorns tightly in, small end first. The surfaces of dead trees are sometimes absolutely covered with such holes, each with its acorn. The woodpecker’s purpose is to wait until the acorns become infested with larvæ. He