Moreover the same notion of metamorphosis may be applied to explain the existence of flowers which are not symmetrical like those we have just referred to, but which have an irregular corolla or calyx. The papilionaceous flower of the pea tribe, which is so markedly irregular, may be deduced by easy gradations from the regular flower, (through the mimoseæ,) by expanding one petal, joining one or two others, and modifying the form of the intermediate ones.
Without attempting to go into detail respecting the proofs of that identity of all the different organs, and all the different forms of plants, which is thus asserted, we may observe, that it rests on such grounds as these;—the transformations which the parts of flowers undergo by accidents of nutriment or exposure. Such changes, considered as monstrosities where they are very remarkable, show the tendencies and possibilities belonging to the organization in which they occur. For instance, the single wild-rose, by culture, transforms many of its numerous stamens into petals, and thus acquires the deeply folded flower of the double garden-rose. We cannot doubt of the reality of this change, for we often see stamens in which it is incomplete. In other cases we find petals becoming leaves, and a branch growing out of the centre of the flower. Some pear-trees, when in blossom, are remarkable for their tendencies to such monstrosities.[82] Again, we find that flowers which are usually irregular, occasionally become regular, and conversely. The common snap-dragon (Linaria vulgaris) affords a curious instance of this.[83] The usual form of this plant is “personate,” the corolla being divided into two lobes, which differ in form, and [472] together present somewhat the appearance of an animal’s face; and the upper portion of the corolla is prolonged backwards into a tube-like “spur.” No flower can be more irregular; but there is a singular variety of this plants termed Peloria, in which the corolla is strictly symmetrical, consisting of a conical tube, narrowed in front, elongated behind into five equal spurs, and containing five stamens of equal length, instead of the two unequal pairs of the didynamous Linaria. These and the like appearances show that there is in nature a capacity for, and tendency to, such changes as the doctrine of metamorphosis asserts.
[82] Lindley, Nat. Syst. p. 84.
[83] Henslow, Principles of Botany, p. 116.
Göthe’s Metamorphosis of Plants was published 1790: and his system was the result of his own independent course of thoughts. The view which it involved was not, however, absolutely new, though it had never before been unfolded in so distinct and persuasive a manner. Linnæus considered the leaves, calyx, corolla, stamens, each as evolved in succession from the other; and spoke of it as prolepsis or anticipation,[84] when the leaves changed accidentally into bracteæ, these into a calyx, this into a corolla, the corolla into stamens, or these into the pistil. And Caspar Wolf apprehended in a more general manner the same principle. “In the whole plant,” says he,[85] “we see nothing but leaves and stalk;” and in order to prove what is the situation of the leaves in all their later forms, he adduces the cotyledons as the first leaves.
[84] Sprengel, Bot. ii. 302. Amœn. Acad. vi. 324, 365.
[85] Nov. Con. Ac. Petrop. xii. 403, xiii. 478.
Göthe was led to his system on this subject by his general views of nature. He saw, he says,[86] that a whole life of talent and labor was requisite to enable any one to arrange the infinitely copious organic forms of a single kingdom of nature. “Yet I felt,” he adds, “that for me there must be another way, analogous to the rest of my habits. The appearance of the changes, round and round, of organic creatures had taken strong hold on my mind. Imagination and Nature appeared to me to vie with each other which could go on most boldly yet most consistently.” His observation of nature, directed by such a thought, led him to the doctrine of the metamorphosis.
[86] Zur Morph. i. 30.
In a later republication of his work (Zur Morphologie, 1817,) he gives a very agreeable account of the various circumstances which affected the reception and progress of his doctrine. Willdenow[87] quoted [473] him thus:—“The life of plants is, as Mr. Göthe very prettily says, an expansion and contraction, and these alternations make the various periods of life.” “This ‘prettily,’” says Göthe, “I can be well content with, but the ‘egregie,’ of Usteri is much more pretty and obliging.” Usteri had used this term respecting Göthe in an edition of Jussieu.