Note: Oranges are the most commonly cultivated citrus fruit worldwide and the most well-known source of vitamin C. You can use them in the kitchen for all types of dishes, no matter whether raw or cooked, and the peel can be used as a seasoning or fragrance.
From Wikipedia: "The orange (specifically, the sweet orange) is the fruit of the citrus species Citrus × sinensis in the family Rutaceae. The fruit of the Citrus × sinensis is considered a sweet orange, whereas the fruit of the Citrus × aurantium is considered a bitter orange. The sweet orange reproduces asexually (apomixis through nucellar embryony); varieties of sweet orange arise through mutations.
The orange is a hybrid, between pomelo (Citrus maxima) and mandarin (Citrus reticulata). ... Sweet oranges were mentioned in Chinese literature in 314 BC. As of 1987, orange trees were found to be the most cultivated fruit tree in the world. Orange trees are widely grown in tropical and subtropical climates for their sweet fruit.
The fruit of the orange tree can be eaten fresh, or processed for its juice or fragrant peel. As of 2012, sweet oranges accounted for approximately 70% of citrus production. In 2013, 71.4 million metric tons of oranges were grown worldwide, production being highest in Brazil and the U.S. states of Florida and California."
"The orange tree is an evergreen, flowering tree, with an average height of 9 to 10 m (30 to 33 ft), although some very old specimens can reach 15 m (49 ft). ...
Although the sweet orange presents different sizes and shapes varying from spherical to oblong, it generally has ten segments (carpels) inside, and contains up to six seeds (or pips) and a porous white tissue – called pith or, more properly, mesocarp or albedo—lines its rind. When unripe, the fruit is green. ...
The Citrus sinensis is subdivided into four classes with distinct characteristics: common oranges, blood or pigmented oranges, navel oranges, and acidless oranges. ..."
Nutritional value and use:
"As with other citrus fruits, orange pulp is an excellent source of vitamin C, providing 64% of the Daily Value in a 100 g serving."
The juice from oranges contains important natural flavoring substances.
"Orange peels are routinely treated with wax (excluding organic oranges), and the wax usually contains preservatives.*"
"Oranges must be mature when harvested. In the United States, laws forbid harvesting immature fruit for human consumption in Texas, Arizona, California and Florida. Ripe oranges, however, often have some green or yellow-green color in the skin. Ethylenegas is used to turn green skin to orange. This process is known as "degreening", also called "gassing", "sweating", or "curing"."
"Oranges, whose flavor may vary from sweet to sour, are commonly peeled and eaten fresh or squeezed for juice. The thick bitter rind is usually discarded, but can be processed into animal feed by desiccation, using pressure and heat. It also is used in certain recipes as a food flavoring or garnish. The outermost layer of the rind can be thinly grated with a zester to produce orange zest. Zest is popular in cooking because it contains oils and has a strong flavor similar to that of the orange pulp. The white part of the rind, including the pith, is a source of pectin and has nearly the same amount of vitamin C as the flesh and other nutrients.
Although not as juicy or tasty as the flesh, orange peel is edible and has significant contents of vitamin C, dietary fiber, total polyphenols, carotenoids, limonene and dietary minerals, such as potassium and magnesium."
"Dried orange peel is used frequently in tea blends, and the blossoms can also be used to make tea.*"
Note (italics): * = Translation from a German Wikipedia entry.