XANTROPHYL. The yellow coloring mat ter of autumnal foliage.
YAK. The Himalayan bison, resembling the buffalo, three and a half feet high, and with fine, longhair.
YAM. The yam—Iguame—Dioscorea elate, is cultivated in every tropical portion of the earth, and also some temperate climates, where the young plants are brought forward early in the season. The Indian archipelago and the south ern portion of the Indian continent is said to be the native homes of this, the most widely culti vated of the Dioscorea family. It was carried thence to the eastern coast of Africa, next to the west coast and from there to America, under the name of yam, which, in the negro dialect of Guinea, means to eat. The other species of yam cultivated, more or less, and all from the Indian archipelago and continent, are Dioscorea penta phylla, D. bulb !era, D. esculenta, and D. deltoi des, (or k'!atara,) the latter being known under both names. The Chinese yam, Diosearea batatas,
was widely disseminated in the United States some years ago, at high prices, and with the assurance that it would supersede the potato. It is entirely hardy, even well North, has some good qualities as an ornamental plant, and the roots have the remarkable quality of remaining sound for years in the ground. In fact it takes several years for them to attain full size. The labor of cultivating this running vine, and espec cially the labor of digging, precludes all profit, if indeed, it were equal as food to the common and sweet potato, which it is not, all of which the introducers ought to have known. They strike their long tubers into the ground, being thickest at the lower end, so that in gathering the earth must be moved to a depth of two feet, or even more