Yam

(yăm.) (Bot.) The popular name of Dioscorea, the typical gen. of the O. Dioscoreaceæ, cla Dictyogens,distinguished by an inferior ovary and membranous winged fruit. The species are mostly tropical, natives of the East and West Indies, . They have tuberous roots and herbaceous twining stems. The great fleshy roots of some of them are very much used as an article of food, in the same way that potatoes are in more temperate climates. They contain much starch, and generally become somewhat mealy and pleasant to the taste when boiled. [s. 973]