MOREHUS OAK (_Quercus morehus_) can never be important in the lumber industry, but it fills a few places in California where the ground needs a cover. Its range is in the northern coast range and the Sierra foothills, extending as far south as Kings river. The edges of the leaves bear bent hooks like saw teeth. The foliage falls in late winter. Trees are occasionally a foot or more in diameter. The wood has not the appearance of possessing much value, and is too scarce to be important. The most interesting thing connected with this tree is that it is supposed to be a hybrid--a cross between highland oak and California black oak. It was first found in 1863, and a considerable range has since been established for it. It is the opinion of some investigators that new tree species have their origin in crosses between existing species. Of the countless thousands of such crosses a few, at long intervals of time, may develop characteristics which enable them to maintain their existence and to spread into new territory. If that occurs, a new kind of tree has appeared on earth and is ready to take its place among the established forests of the region. Cross-fertilization among trees and plants is very common, but so many adverse conditions are encountered, that few hybrids ever amount to anything. [Illustration] PIN OAK [Illustration: PIN OAK] PIN OAK (_Quercus Palustris_) Pin oak ranges from certain sections of Massachusetts, notably the Connecticut river valley, and near Amherst, westward as far as the southeastern part of Missouri; on the south it is found along the lower Potomac river in Virginia, in Kentucky, Arkansas, and Oklahoma. It is known as pin oak in Massachusetts, Connecticut, Rhode Island, New York, Pennsylvania, Delaware, Virginia, Maryland, Arkansas, Missouri, Illinois, Wisconsin, Iowa, and Kansas; in Arkansas and Kansas it is called swamp Spanish oak; in Rhode Island and Illinois it is often known as water oak; in Pennsylvania, Ohio, and Kansas as swamp oak; in Arkansas as water Spanish oak.