Oranges (Citrus aurantium).
—This fruit is characterized by its delightful flavor and by the distribution of certain aromatic oils, especially in the rind, which give it a peculiar aroma and flavor. The orange has a thick yellow rind which, while edible, is not usually eaten, but is the source of valuable essential oils. A large part of the orange, as far as weight is concerned, is not usually eaten; usually from 25 to 40 percent of the weight is in the rind or some inedible portion. The ash of the orange is usually less than one-half of one percent. The predominant organic acid of the orange is citric, although other organic acids are present. The quantity of protein present in an orange is very small, usually not exceeding very much a half of one percent. The quantity of sugar varies greatly in different samples. It is present both as cane sugar or sucrose and as reducing or invert sugar. In the very sweet orange the quantity reaches as high as 10 percent or even greater, while in the sour orange it is less. The principal food value of the orange, as far as nutriment is concerned, is its sugar. The orange, however, has other valuable properties, especially from a hygienic standpoint, aside from its nutriment. The organic salts which it contains, the organic acids, and other condimental material make the orange an exceptionally wholesome fruit, exercising a beneficial effect upon the digestive process and especially aiding in the passage of the undigested food through the alimentary canal. The orange is a fruit which has lasting keeping qualities. It is not unusual to see ripe oranges which are edible hanging on the same tree with the blossoms which are blooming for the next year’s crop. In California and Florida the oranges begin to ripen in November and may be continuously harvested until the following April, if it be advisable to leave them on the tree for that length of time. Owing to the thick and resistant skin of the orange, it can be kept for a long time without material deterioration after harvesting, if care be taken to avoid bruising or injuring the fruit in any way while handling. Oranges thus harvested and wrapped in paper and kept at a low temperature will keep for weeks and even months, and still be edible and nourishing. This property of the orange makes it possible to supply the markets of the world practically throughout the entire year with one of the most delicious and nutritious of fruits. In former years the orange was regarded as a luxury, but at the present time it is a staple article of diet even for people in moderate circumstances, and is often eaten by those who are poor. In [Fig. 53] is given a typical illustration of a California orange grove.
Fig. 53.—An Edge of a California Orange Grove.—(Bureau of Plant Industry.)
The culture of the orange has demanded the highest agricultural and scientific skill, and perhaps there is no crop produced to which greater attention has been paid. In Florida, especially, the oranges are grown on soil which is not much more than poor sand, and hence the scientific feeding of the trees, that is, the fertilization of the soil in which they grow, is necessary to success. As a result of this application of science luxuriant crops of oranges are found growing upon sandy soil which without scientific treatment would be almost barren. The soils in southern California, on the other hand, are very rich in natural plant food, but this does not obviate the necessity of scientific manuring. Oranges grow throughout the year in tropical and semi-tropical regions. It is considered by connoisseurs, however, that the oranges grown in the semi-tropical regions, that is far enough north for a little frost to come during the winter, but without a sufficient degree of cold to injure the trees, are of better quality than those grown in tropical regions where frost is unknown.
Fig. 54.—The Original Seedless Orange Tree.—(Courtesy Bureau of Plant Industry.)
The Seedless Orange.
—The variety of orange which contains no seed has been widely cultivated in the United States, and by reason of the absence of seeds is more highly prized by many than the ordinary orange for edible purposes. Since the orange tree has been cultivated by grafting rather than by direct production of the different varieties from the natural seed, it has been possible to secure a fruit without seeds. Whether such an unnatural product will continue to maintain its high rank as an edible product remains to be seen. The seedless orange tree, from which are descended the greater part of these trees in the United States, was secured by Mr. William Sanders from Bahia. Its present appearance in the greenhouse of the Department of Agriculture is shown in [Fig. 54]. The naval orange is exceedingly beautiful as it grows upon the tree. A bunch of these oranges growing on the parent tree in Washington is shown in [Fig. 55].
