One of the most far-reaching in its possibilities of all the introductions of the Office is the drought resistant durum wheats, which yield crops where all ordinary wheats fail for lack of water. Largely through Mr. M. A. Carleton's effort, this grain, un known on American grain markets seven years ago, is now grown in such quantities that in 1905 the United States exported 6,000,000 bushels of it. Another introduction was the Japanese Kiushu rice, which was in part responsible for the great develop ment of the Texas and Louisiana rice-fields and which is now planted on one-half the rice area of these states.
These problems, chosen from among the many engaging the attention of the Department special ists, should give an idea of the way in which this branch of the government is affecting the agricul ture of the country.
Other interesting or important food plants that the Office is introducing or disseminating are shown in Figs. 93 to 99. These are products of well-known species and need not be further de scribed here.
A feature of the in troductions that de serves especially to be mentioned, since it is growing rapidly in im portance, is the getting of material for those en gaged in breeding new races of plants. In order to break up a species it is often necessary to cross it with some nearly related species, and such near relatives are often wild plants or forms that are not to be found in this country. It is one of the pleasant parts of the work to secure a plant from the ends of the earth that some breeder may incorporate it into a new hybrid of value. The citrange of Messrs. Swingle and Webber would not have been made had not an ornamental, the Citrus trifoliata, been introduced from Japan ; the inter esting tobacco crosses that Mr. Shamel has made owe their origin in part to the fact that he had Sumatra seed to work with ; the interesting series of hybrid cottons that Dr. Webber has been work ing with are the results of cross-pollinations be tween the American and Egyptian cottons. To help Mr. Swingle in his work on the pistachio-nut, which may prove a new nut industry for California, the Office is searching for a Chinese species that will resist cold, a species native in Afghanistan that will resist alkali, the mastick and terebinth of southern Europe, and a native Texan species that Mr. Swingle thinks will be valuable for use as
stocks. The problem of the introduction of the tropical mangosteen of the Dutch East Indies is being worked out by Mr. Oliver, the expert propa gator of the Department, chiefly through the use of as many of the nearly related species of the genus Garcinia as can be brought together. There are over sixty species in this tropical genus, and, as fifteen of these bear edible fruits, it would be strange if at least one should not be available as a stock or of worth for breeding purposes. The suc cessful introduction of this, the most valuable of East Indian fruits, probably hangs on the utilizing of some of these other and more vigorous species of Garcinia.
Most fortunately for the Office, the possibilities of plant-introduction work appealed at the outset most strongly to the practical mind of a past master in the art of travel, who for over forty years has wandered almost constantly over the world,—Mr. Barbour Lathrop, of Chicago. Seeing such widely different crops in the many lands that he visited, his unusual foresight saw in the work of plant introduction a great wealth - creating power, and, convinced of the good he could do for his country by aiding its progress, he spent the greater part of his time and en ergy during the years of 1896, 1898-99, 1901-02, and 1903 in making, at his own expense, a tour of reconnaissance of the world in the interest of the Office of Plant Introduction. He took the writer with him as his agri cultural explorer, and estab lished correspondents in most of the principal points of plant in terest in the world. This list of correspondents is one of the great assets of the Office, enabling it to secure quickly from any re gion the seeds or plants desired for hosts of experiments which the Office is pressed by private experimenters to take up. In the course of these six years of travel a mass of material was imported from all parts of the world, aggregating at least 1,200 different selected things that seemed worthy of trial in Amer ica. Many of these are now form ing subjects of study and exper iment in different parts of the country and have been alluded to under the successes achieved or the problems now being worked out by the Department specialists.