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.
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.