YA-LUITG-KIANG, ylifIng'kylime. A river of Western China, rising on the southern slope of the Bayan-kara, an eastern extension of the Kum-11m Mountains in Eastern Tibet, near the headwaters of the Yellow Biver, latitude 34° N. and longitude 97° E. (Map: China, B 0). Its course is generally south through deep gorges parallel with the Kin-sha-kiang or Yang-tse, which it joins after a course of several hundred miles in latitude 26° 35' N. It is a very swift stream, much impeded by rapids, and is not navi gable except in local stretches.
YAM (from Sp. name. iiianze, ignanic, ignama, Port. inhume, yam, from African nyainc, yam), Dioscorea. A genus of mostly East and West Indian plants of the natural order Dioscoreaeete, distinguished by an inferior ovary and mem branous winged fruit. They have herbaceous twining stems, and fleshy roots which in some species are used as food, like potatoes. They t-'in much starch, and generally beeome some what mealy and pleasant to the taste when boiled. The tubers of all the yams contain an acrid substanee, which, however, is dissipated by boiling, except in the species with compound leaves. The winged yam alatal has roots to 3 feet long, and often 30 pounds in weight, with a brownish or black skin, juicy and reddish within. They vary exeeedinglv in form.
Small tubers are generally found in the axils of the leaves. This species is the original of most. or perhaps all, of the yams cultivated in tropical Asia, Africa, and America: the common yam of the West Indies (Dioscorca saliva), which has a round stem and heart-shaped leaves; Dioscorca ',Whiter'', in which the tubers in the axils of the leaves attain the size of apples; the prickly yam (Dioscorca aeuleata), which has a prickly stem, and a faseiculated. tuberous root; Dioscorea globosa, the most esteemed yarn of India, which has very fragrant flowers, and roots white in ternally; Dioscorca rubella, another Indian kind. with tubers sometimes 3 feet long, tinged with red below the skin, etc. The Chinese yarn (Dioscorca divaricata) is a perfectly hardy sort. Its edible club-shaped roots descend perpendicu larly into the ground from two to three feet. and largely on this account it is little cultivated.