The humid portion of the lower austral province extends northward from the Gulf strip, and presents a transition in climatic conditions between the semitropical Gulf coast and the more markedly temperate climate of the upper austral. This eastern division of the lower austral, characterized by its mild winters, general absence of snow, long hot summers with abundant rain, extends from eastern Virginia southward about the southern end of the Appalachian Mountains, and in the Mississippi Valley broadens so as to reach the mouth of the Ohio River. Its western limit is in central Texas, where the mean annual rainfall decreases to less than 20 inches, and forests give place to treeless, grass-covered plains and plateaus. Through this eastern portion of the lower austral the mean annual precipitation is in general between 50 and 60 inches, and is so distributed throughout the year that each month receives approximately an equal share. In general, however, the rainfall is greater in winter than in summer. The mean annual temperature of the humid portion of the lower austral is from 60 deg. to 68 deg. F., the mean winter temperature 40 deg. to 52 deg., and the mean summer temperature from 75 deg. to 80 deg. F. From these records it may be inferred that the conditions are favourable for the growth of trees. In its natural condition this entire region was clothed with a varied and beautiful forest, consisting largely of broad-leaved trees, but is also the home of the southern pine and the cypress. The characteristic crops are cotton and corn (maize). The western or arid portion of the lower austral province embraces western Texas, a large area in northeastern Mexico, and circling about the southern extremity of the Pacific mountains in central Mexico, extends northward adjacent to the tropical border of the Pacific and the Gulf of Lower California, into Arizona and southern California. A detached area of this same province occupies the great Valley of California.