Part 84. Artificial systems. An attempt was made to overcome the above objection regarding unnatural separation of sorts much alike, by calling the larger shrubs, trees, and the smaller ones, herbs, thus doing away altogether with the intermediate division. This, of course, lessened the difficulty in a way, but can hardly be said to have removed it. To make smaller groups, these two were again subdivided according to differences observed in this or that part. Thus, some writers made subdivisions according to the shape or arrangement of the leaves; others according to the form of the fruit or seeds; others still, according to peculiarities of some part of the flower; and so on, each writer basing his system upon characters taken from one or two parts. Many attempts of this sort were made during the next two centuries.

Some of these systems were decided improvements over the earlier classification, but even the most elaborate of them had the same fundamental weakness already pointed out in the arrangement according to size. We know that plants which differ a good deal as regards a single part may be very much alike in all other respects, while plants much alike in a certain part may be otherwise very different from one another. For example, the fruits of the almond and the peach differ much in appearance when ripe, but otherwise an almond-tree and a peach-tree are almost exactly alike. On the other hand, the root of the beet and of the turnip are often of exactly the same shape, while the plants are strikingly different in all other respects. It is plain, therefore, that any arrangement of plants based upon a single character or very limited set of peculiarities, is bound to be unsatisfactory, because it cannot accomplish the chief purpose of a classification, namely, to group nearest together the sorts that are most alike. In a word, these systems failed chiefly because they are artificial, and so not well calculated to express the resemblances and differences among plants as we find them in nature.

On the whole, as we have said, these artificial systems served to advance botanical knowledge; although after a while the increasing number of them became a serious burden to all who studied plants. Any system, it was thought, if only used by all, would be much better than having to use so many.

At last a practical way out of the increasing confusion was found by the clear-sighted Linnaeus who came to the rescue much as he had done in the matter of plant names.