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cultivation

(Encyclopedia)cultivation, tilling or manipulation of the soil, done primarily to eliminate weeds that compete with crops for water and nutrients. Cultivation may be used in crusted soils to increase soil aeration ...

mandrake

(Encyclopedia)mandrake, plant of the family Solanaceae (nightshade family), the source of a narcotic much used during the Middle Ages as a pain-killer and perhaps the subject of more superstition than any other pla...

meristem

(Encyclopedia)meristem mĕrˈistĕmˌ [key], a specialized section of plant tissue characterized by cell division and growth. Much of the mature plant's growth is provided by meristems. Apical meristems found at th...

ginger

(Encyclopedia)ginger, common name for members of the Zingiberaceae, a family of tropical and subtropical perennial herbs, chiefly of Indomalaysia. The aromatic oils of many are used in making condiments, perfumes, ...

exponent

(Encyclopedia)exponent, in mathematics, a number, letter, or algebraic expression written above and to the right of another number, letter, or expression called the base. In the expressions x2 and xn, the number 2 ...

pi

(Encyclopedia)pi, in mathematics, the ratio of the circumference of a circle to its diameter. The symbol for pi is π. The ratio is the same for all circles and is approximately 3.1416. It is of great importance in...

Lindsay, John Vliet

(Encyclopedia)Lindsay, John Vliet vlēt [key], 1921–2000, American politician, mayor of New York City (1966–73), b. New York City. He practiced law and then served (1955–57) as executive assistant to Attorney...

Arms, John Taylor

(Encyclopedia)Arms, John Taylor, 1887–1953, American etcher and draftsman, b. Washington, D.C. He studied architecture, but later he devoted himself to etching and became noted for his excellent studies of mediev...

La Farge, John

(Encyclopedia)La Farge, John lə färzh [key], 1835–1910, American artist and writer, b. New York City. He studied with William Morris Hunt in Newport, R.I., and with Thomas Couture in Paris. La Farge began his c...

Kellogg, John Harvey

(Encyclopedia)Kellogg, John Harvey, 1852–1943, American physician, health-food advocate, and breakfast cereal developer, b. Tyrone, N.Y., grad. New York Univ. (M.D., 1875) and continued his medical studies in Eur...