This tree belongs to the rose family, and the genus _Cratægus_ consists of a large group of small, thorny trees, scattered through many parts of the world. They are known by their thorns, but comparatively few of them are known by name to the ordinary observer, and they afford a perpetual source of study, victory, and bewilderment to the trained botanist. “No other group of American trees,” says Sudworth, “presents such almost insurmountable difficulties in point of distinctive characters. It is impossible, and fortunately unnecessary, for the practical forester to know them all, and exceedingly difficult even for the specialist.” More than one hundred species of these thorn trees occur in the United States, exclusive of shrubs. Their bloom resembles that of apple and pear trees. Bees and insects swarm round the flowering trees, assisting in cross fertilization. The various species are aggressive. They force their way into vacant spaces, and their thorns protect them against browsing animals. The wood is sappy and heavy, and for most of the species it is valueless. The growing brambles, however, perform an important service in forest economy. Seeds of various valuable trees are blown by wind or carried by birds and mammals into the thickets where they germinate and get a start under the protecting shelter of the thorns. Finally the seedlings overtop the brambles, gain the mastery, shade the thorns to death, and develop valuable forests. The thorn trees shed their leaves annually. Their seeds are slow to germinate, some not sprouting until the second year. The fruit is worthless for human consumption, but some of it has a tart and not unpleasant taste. It is of many colors and sizes, depending on species. No attempt is here made to name or to list the species. Such a list would, for most people, be a dull catalogue of names, and many of them in Latin because there are no English equivalents. A few representative species are given. The red haw, though not the most abundant, is widely distributed, and is probably as well known as any. Its range extends from Newfoundland westward through southern Canada to the eastern base of the Rocky Mountains, thence south to Texas and Florida. It covers one-half of the United States. In the northern part of its range the red haw is confined to the slopes of low hills and along water courses, but south in the Appalachian mountains it grows at an elevation of several thousand feet. It has various names in different regions. It is called scarlet haw, red haw, white thorn, scarlet thorn, scarlet-fruited thorn, red thorn, thorn, thorn bush, thorn apple, and hedge thorn. The fact is worthy of note that it is well known and is clearly recognized in every region where it grows, though various names are given it.