Onion (from unio, the Latin name for a large kind of onion), the common name of the plant allium cepa. The genus allium (the ancient name for garlic) includes, besides several wild species, the cultivated garlic, leek, shallot, and chives. It belongs to the lily family, and is distinguished from related genera by its coated bulb, a naked scape, bearing at the top a simple umbel from a one- or two-leaved spathe, which soon becomes dry, and six-parted flowers, the divisions of which are white or colored and one-nerved; the style thread-like, stigma simple, fruit a three-lobed, three-celled pod, with one or few seeds in each cell. All species have the pungent taste and odor known as alliaceous. The leaves in the onion (A. cepa) are cylindrical, hollow, and shorter than the inflated flower stalk, and the flowers white; in this, as in some other species, small bulblets are sometimes produced in place of the flowers. Its native country is supposed to be western Asia, probably between Palestine and India; species so nearly related that they have been taken for A. cepa are found in Siberia. The onion was among the earliest cultivated vegetables, and in Egypt was a sort of divinity.

The plant is a biennial, forming a bulb the first season from the seed, and the next year throwing up its flower stalk, producing seed, and perishing; but there are deviations from this, and there are two distinct races which reproduce differently. The potato onions, also called multipliers, do not produce seed or even flowers, but form a great number of small bulbs; one of these, the size of a walnut or smaller, planted in the spring, will grow to a large bulb, which if set out the next spring will produce numerous small bulbs of different sizes. Another race is the top or tree onion, which instead of flowers produces at the end of the stalk a cluster of small bulbs or onions about the size of a filbert; these when planted will grow to a good size, and if the bulbs thus obtained are set out the next spring, they will produce a crop of small bulbs. Neither of these sorts is much cultivated except in private gardens, but the great supply is furnished by the ordinary seed-bearing kind. In most northern localities the seed is sown in spring and the bulbs mature in early autumn; south of New York the development of the bulbs is arrested by dry weather, and without irrigation the crop will usually fail; in such localities onions are raised from sets, small bulbs of the size of a pea or larger grown the season before; the seed is sown very thickly in rather poor soil, and the bulbs ripen when very small; these sets are kept until spring, and planted instead of seed.

In localities where the winter will allow, the seed is sown in August, and the young plants, left in the ground all winter, start early the following spring. In parts of Hartford co., Conn., Orange co., N. Y., Rhode Island, and in some localities of Iowa and other western states, onions are the staple product. They can be grown upon the same ground year after year without deterioration, and there are cases in which the same land has produced onions continuously for half a century or more. High manuring is required. The seed (always of the previous year) is sown by a machine in drills about 15 in. apart as early as possible; as soon as the plants appear weeding is begun, and it is continued unremittingly as long as there is need of it. The maturity of the bulbs is shown by the falling over of the tops; some plants will not form good bulbs, or "bottom out," but remain with a thick stem like a leek, and are known as seal-lions. The onions are pulled, and allowed to cure in the sun a few days. In storing for the winter they must not be in quantities large enough to heat; freezing does not injure them if they thaw gradually.

Seed is raised by setting out well kept selected bulbs in rich ground, giving support to the flower stalks by means of stakes and strings, and gathering before the seed shells out. The varieties are numerous, though there are but few which are regarded as standard; there are red, yellow, and white-skinned onions, and of each of these flat, globular, and oval forms; the Weathersfield red, yellow Danvers, and white Portugal or silver-skin are the most grown. Italy, Spain, Mexico, and California are noted for the great size and fine quality of their onions, but the superiority is due to soil and climate rather than to the variety. The great enemy to the crop is a maggot, the larva of anthomyia ccparum, a small fly, known as the onion fly; it lays its eggs on the small plants near the ground, and the maggot finds its way to the forming bulb, which it feeds upon and kills; no practicable remedy has been found for this, or for a smut which sometimes appears on the young plants. The odor of onions is due to a volatile oil similar to if not identical with that of garlic, and their physiological effects are similar, but milder; they are largely used as seasoning, and are eaten both raw and cooked; boiling dissipates much of the oil. - The so-called Welsh onion is curiously misnamed, as the plant (allium fistulosum) is a native of Russia, where it is known as the rock onion.

It does not form a bulb, but produces numerous coated stems much like small leeks; it is little cultivated in this country, but is useful in high latitudes where the common onion cannot be grown. The French, who call it ciboulc, have a red and a white variety. - Cives or chives (A. schanopra-sitm), the smallest of the genus in cultivation, is found on the shores of Lakes Huron and Superior and northward; it has small oval bulbs not over half an inch in diameter, numerous small cylindrical leaves about 8 in. long, and clusters of purplish, not inelegant flowers; it rarely matures seeds, but the bulbs are produced by offsets in great numbers, and form dense clumps several inches in diameter; it is propagated by dividing the clumps. The leaves are used, cut when young and tender.

Potato or Multiplier Onions.

Potato or Multiplier Onions.

Top Onions, Natural Size.

Top Onions, Natural Size.

Cives (Allium schoenoprasuni).

Cives (Allium schoenoprasuni).