Battle of the Yalu

YALU, BATTLE OF THE. This was the opening battle on land of the RUSSO-JAPANESE WAR, and is described under that heading. Fought on May 1, 1904, by Gen. Kuroki's I. Army, ad vancing from Korea, the Japanese success was a valuable moral tonic and created a profound impression in Europe.

YAM,

a term usually applied to the tubers of various species of Dioscorea of the monocotyledonous family Dioscoreaceae. These are plants with thick tubers (generally a development of the base of the stem), from which protrude long, slender, annual climbing stems, bearing alternate or opposite, entire or lobed leaves and unisexual flowers in long clusters. The flowers are gen erally small and individually inconspicuous, though collectively showy. Each consists of a greenish, bell-shaped or flat perianth of six pieces, enclosing six or fewer stamens in the male flowers, and surmounting a three-celled, three-winged ovary in the female flowers. The ovary ripens into a membranous capsule, bursting by three valves to liberate numerous flattish or globose seeds. The species are natives of the warmer regions of both hemispheres.

D. sativa and D. alata are the species most widely diffused in tropical and subtropical countries. D. aculeata, grown in India, Cochin China and the South Sea islands, is one of the best varie ties. D. Batatas, the Chinese yam, or Chinese potato, is hardy in Great Britain, but the great depth to which its enormous tubers descend renders its cultivation unprofitable. It has deeply pene

trating, thick, club-shaped, fleshy roots, full of starch (about 13% of the fresh weight) which when cooked acquire a mild taste like that of a potato ; they grow 3 ft. or upwards in length, and some times weigh more than 12 lb. The plant grows freely in deep sandy soil, moderately enriched. The tubers of D. alata sometimes weigh Ioo lb. Most of the yams contain an acrid principle, which is dissipated in cooking.

The only European species is D. pyrenaica, a native of the Pyrenees, a remarkable instance of a species growing at a long distance from all its congeners. In North America there is a single native species, D. villosa, called wild yam-root or colic-root. This is found from Rhode Island to Ontario and Minnesota and south ward to Florida and Texas, but is of slight economic value. True yams must not be confounded with the sweet potato, Ipomoea Batatas. The common black bryony (Tamius communis) of hedges in England is closely allied to the yams of the tropics, and has a similar root-stock, which is reputed to be poisonous.

For the history of the yam, and its cultivation and uses in India,

see G. Watt, Dictionary of the Economic Products of India, iii. (189o).