The available space will not permit of a fuller discussion of the very numerous and elaborate systems of classification proposed by European pomologists. Those already given will indicate the leading ones. It will be noted that even in the most complete natural systems several classes, based mainly on artificial external characters, are necessary to provide a place for many varieties not readily classified otherwise.
After reviewing the many systems of classifying apples, many of them very elaborate and the product of much painstaking labor and research, the writer offers the following conclusions:
I. The arranging of apples into families based on natural affinities is a great aid to the memory. This is true of all systems of natural classifications.
II. If all varieties of apples were sharply defined in their characteristics the natural systems, as those of Diel and Lucas, would be of easy application, if properly combined with an artificial classification based on form, season, etc., as outlined by Lucas. But many varieties present characteristics which are a mingling of two or more classes, and these defy all attempts at close classification.
III. It would be of considerable help to arrange apples as far as possible by groups named after the most typical representative of that group. American pomologists now often speak of the Ben Davis type or group, being that well-known variety and what are probably its numerous seedlings; the Fameuse type, comprising a number of sorts with close affinities to the mother variety; the Oldenburg type, which is a very large one in the Northwest owing to the wide popularity of that variety; the Hibernal type, including a number of extra hardy Russians. In Minnesota the numerous seedlings of Wealthy now appearing show close affinities to its parent. This modern development of the natural classification idea merits further study.
IV. The marvellous development of commercial orcharding in recent years has not been favorable to increase in number of varieties. Commercial fruit-growers prefer the few of best sorts rather than a large assortment with few trees of a kind. Hence the need for classification of varieties is not yet as apparent as in Europe where a greater variety is demanded in the small specimen orchards.
V. The belief of Downing that the classification of the apples of the United States is impracticable, if not impossible, is probably nearer to the truth than any belief to the contrary. It could be done with the apples for any particular region with not too large an area. On the other hand, the alphabetical or dictionary style of arranging descriptions is not serviceable when the name of the fruit in hand is not known.
VI. A purely artificial key is, in the opinion of the writer, a feasible solution of the problem. Every variety has its distinguishing characteristics or "ear-marks" by which it is known to those familiar with it. In addition to the characters usually given in American descriptions should be added the internal points noted by Hogg, Lucas, and other European writers. It does not appear an impossible task to arrange all these various points, so that the reader, with an unknown variety in hand will need to read through a few varieties only instead of all. The magnitude of this proposed work places it beyond the boundaries of private or State enterprise and makes it an undertaking of national scope.