These are among the most useful of trees, and besides, they form graceful ornaments in strcets and fields. They have small flowers collected in balls or spikes of a white, red or yellow color. They inhabit all the warm countries of the world; some of them yield gum arabic, others gum senegal. The bark of one variety gives ns the astringent substance called catechu, or te!'ra japonica. The flowers of some are extremely fragrant, and are much used in Italy as a perfume. Many species have a bark possessed of valuable tanning properties. The timber is very durable, and it requires little or no cultivation. The Chinese nse the yellow flowers to dye silks wfth, and it gives a color which is, as yet, unrhaled. One genus is known here as the Locust tree, and it is worthy of more general attention.