The onion has been grown since remote antiquity. The oldest historic records frequently refer to its culture and its use as an article of food. It probably originated in the southern part of Europe or in countries bordering on the Mediterranean Sea. A great variety of types has been developed. The most marked progress in the breeding of the modern globular bulb has been made within the last 25 years.
The onion belongs to the lily family, which also includes the asparagus. It is generally a biennial, although some forms, as the multipliers, are perennial. Usually it is grown as an annual for the bulbs, and sometimes for the tops, which are used in seasoning. True stems are not produced. The portion above the bulb is often as valuable for food as the bulb itself. The bulbs are variable in color, being white, yellow, red and intermediate shades of these colors. The seed stalks are long, slender and hollow. They bear dense, showy, round heads of small white or lilac-colored flowers. Instead of producing flowers, some forms, as "tree" and "top onions," produce clusters of sets or bulblets which are planted to produce bunching onions or mature bulbs. The seeds are black, angular and flattened.
This is one of the most important vegetables in the world, being grown in nearly all countries and ranking third in commercial importance in the United States. (U. S. D. A. Farmers' Bulletin 354, p. 5). Fourteen million bushels, valued at $10,000,000, were grown in this country in 1908. The annual importations from Spain, Egypt, Bermuda and the South Sea Islands amount to about 1,400,000 bushels. Its wide adaptation to different soils and climatic conditions and its general use the year round for culinary purposes properly give it a place among our most useful vegetables. It is universally planted in the home garden and the commercial areas occupy thousands of acres. The crop offers special inducements for the employment of intensive methods, as the possibilities of profit are greater than for most classes of vegetables.