Colorado River into the Salton Basin. It will be remembered that in the autumn of 1904 an irrigation ditch was eroded into a stream that carried an enormous amount of water from the river into the sink—at its lowest level 280 feet below that of the sea—and formed a lake some five hundred square miles in extent, which threatened to extend and submerge a flourishing district. After repeated failures and the expenditure of several million dollars, the overflow was checked early in 1907. The submergence of this area and its drying up have caused and will cause changes in the vegetation which may throw light on the distribution of plants, and the Department of Botanical Research of the Carnegie Institution, under the direction of Dr. D. T. MacDougal, with its Desert Laboratory at Tucson, Arizona, was in a position to take up this problem. It has been extended to the Pattie Basin, into which flood water escapes nearly every year. The general plan of the work is described in the last Year Book of the institution, from which the accompanying
