YAM

the tuberous root of a climbing plant of the Dioscorea—D. alata including all the most important varieties of common cultivation. They resemble sweet-potatoes in general characteristics and are largely used as food in the West Indies and other tropileal regions, and to a small extent in Florida and Louisiana. Big specimens frequently weigh thirty pounds or more and oveasionally exceed 100 pounds and a length of seven or eight feet. The small roots are, however, usually the choicest—some of them represent both the most delicate flavor and the highest food value of all starchy vegetables. To bring out their full merits they should be very thoroughly boiled. The batatas species, the ‘‘Chinese vam,’’ is hardy in temperate climates and yields fleshy, club-style, palatable roots that may exceed three feet in length. It is, however, le desirable for cultivation because of its deep-growing habit. Commercially unimportant but interesting horticulturally are the ‘‘air potatoes”’ of the baliifera species, borne above ground fruit-stvle among the leaves of the vines. They are variable in shape (except that they are nearly always angular) and may weigh several pounds. They are good eating, resembling the ordinary potato in flesh and flavor. They should not be confused with the potato-shaped, bitter tubers of another variously placed vine also known as ‘‘air potato,’’ or ‘‘giant yam vine.”’ Despite the southern cultivation of the true yam, the ‘‘yam’’ of southern markets is generally a large sweet-potato.