Compare that restricted range with that given by the same author twenty-five years later in his “Manual of the Trees of North America.” He gives it thus: “Northeastern Iowa and central Illinois, through southern Illinois and Indiana and western Kentucky and Tennessee, to the valley of the Apalachicola river, Florida, northern Georgia, central South Carolina, and the coast plains of North Carolina, and through southern Missouri, Arkansas, and Louisiana to the mountains of western Texas; most abundant and of its largest size on the low bottom lands of the Mississippi basin, often forming a considerable part of lowland forests; less abundant in the eastern Gulf states; in western Texas on low limestone hills and on bottom lands in the neighborhood of streams.” This quotation is given in full because it shows how scientific men change their opinions to conform to new evidence. The range of that particular species was as wide in 1880 as in 1905, but botanists had not yet worked it out. Thus knowledge increases constantly, and year by year the resources of American forests are better understood. In this instance, what in 1880 was supposed to be a rather insignificant variety, occupying a restricted area in Texas, was found by 1905 to be a separate species, covering sixteen states in whole or in part. Similar progress concerning the forests has been made all over the country, not only by botanists but by lumbermen. Trees which were formerly considered so nearly alike that no distinctions were made, are now recognized to be quite different. The Texan red oak is frequently called spotted oak. The appearance of the bark suggests the name. Large, irregular, whitish patches cover the trunks. That peculiarity is not noticeable everywhere and on all trees, but is common west of the Mississippi river. The tree is sometimes known as Spanish oak in the southwestern part of its range, but the name is ill-advised, for the true Spanish oak (_Quercus digitata_) occurs in the same region. The most usual name for this species, in nearly all parts of its range, is simply red oak. The Texan red oak varies greatly in size of trees, as is natural in so wide a geographical range. Trees have been reported 200 feet high and eight feet in diameter; but sizes like that are extraordinary and attempts to locate anything approaching them at this day have not been successful. The average in the lower Mississippi valley is eighty or ninety feet in height, and two or three in diameter. In Texas this size is seldom reached, the average not much exceeding half of it.