OF TILE CLASSIFICATION OF PLANTS.
The species of plants, as well as of all other natural productions, are so im mensely numerous, that the most super. facial observer must be aware of the ne cessity of some regular mode of arrang ing them, as well as of naming and dis tinguishing them, in order to acquire or to retain any clear knowledge of their na tures, differences, or comparative uses I fence the distribution of plants into trees, shrubs, and herbs, into eatable, medici nal, or hurtful kinds, was very early con ceived ; for the human mind is naturally prone to method and combination. When the subject came to be scientifically stu died, various plans were formed, as dif ferent in ingenuity and utility as possible, proceeding on various principles, but all aiming at the same end, the commodious arrangement of plants. The authors of these various schemes seem all, as far as they considered the matter with any such view, to have thought their own plan most consonant with that natural classifi cation, which every one at first sight per ceived to exist in the creation ; but a little experience proved that the clue of nature soon eluded their grasp.
Linnreus, the first person who took a very comprehensive and philosophical view of the laws of system, and at the same time carried them most happily into effect, for the purpose of utility and facility, was the first to perceive the difference be tween a natural arrangement and an arti ficial one. He ever considered the former as the great desideratum of philosophical botany, and indeed as necessary to be kept in view by all who describe or de. fine new discovered plants ; while the latter was to be adopted for ready use and convenience, just as words are arranged in a dictionary according to their spell ing, without any regard to their deriva. tions or analogical meanings. The same great naturalist was also, from the first, aware of the essential importance of the principle laid down by Gesner and Ce salpinus, as we have already stated, that plants ought to be arranged by their parts of fructification alone, and not by their general habit or structure indepen dent thereof. Hence he denominates heterodox, all such systematics as class vegetables by their leaves, roots, uses, times of flowering, or places of growth, for, strange to tell I there have been such ; and he esteems truly orthodox, those botanists only who derive the cha.
racters of their systems from the flower and fruit, in which, as he expresses it, the true form or essence of their being is dis. played. On this point all botanists are now agreed, but they differ widely concerning the eligibility of a natural or an artificial system for daily use, as well as the princi ples upon which each ought to be founded.
The earlier systematics began with the consideration of the seed and seed-vessel, forming their classes upon the situation of the embryo, whether at the top or base of the seed, and the number of the seeds and seed-vessels, or their cells, in differ ent plants. Some, as the great English naturalist, Ray, took into consideration, over and above the fruit and its parts,the form and number of the parts of the co rolla, and even the leaves and roots,which altogether make but a motley jumble of principles ; but in a second attempt, this learned man was more uniform and suc cessful in his scheme. Others founded their systems on the corolla alone, as Ri vinus and Tournefort, whose methods are elegant and attractive at first sight, but far more unphilosophical, far more diffi cult in practice, than those founded on the fruit. The authors of these various systems disputed with great warmth con cerning theirrespective merits, and each had his followers and advocates. Many other methods were contrived, partaking, more or less, of the principles of the few great leading systematics who contended for the botanical sceptre, and frequently borrowing from them without due ac knowledgment. All these systems have now passed away, at least with respect to practical use. They are the study of the botanical antiquary, and they are instruc tive to the student of philosophical ar rangement in general ; but no work that treats of plants is arranged by their laws, nor does any practical botanist waste his thoughts or judgment in comparing their different merits.