Vegetable morphology : its history and present condition / by Maxwell T. Masters.

  • Masters, Maxwell Tylden, 1833-1907.
Date:
1862
Catalogue details

Licence: Public Domain Mark

Credit: Vegetable morphology : its history and present condition / by Maxwell T. Masters. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    of which has not been sufficiently recognised till comparatively reeently. He describes the internal structure of buds as consisting of a cellular substance to which the rudiments of the leaves are to be considered as a^jpendicular organs. He attributes the formation of the flower to an ari’est of growth arising from diminished vegetative action. The order of development in the successive whorls of the flower is explained by Wolf in a manner not quite in accordance with modern researches on this subject; nor is his hypothesis, that the stamens are to be considered as buds axillary to the petals, at all consonant with their true position with reference to the ])etals. This notion, however, somewhat modified, has of late years been supported by Agardh and Endlicher. In reference to the metamorphosis of plants, neither Linnmus nor Goethe have expi'cssed themselves so clearly as does Wolf in an essay on the Development of the Intestinal Canal in the Chick, published in the Commentaries of the St. Petersbui’g Academy of Sciences, 1766. After speaking of the homologous nature of the leaves, the sepals and petals, an homology consequent on their similarity of stnicture and identity of origin, he goes on to state that the “pericarp is manifestly coinpo.sed of several leaves as in the calyx, with this difference only, that the leaves which are merely placed in close contact in the calyx, are here united togethera view which he corroborates by referring to the manner in which many capsules open and separate “into their leaves.” The seeds, too, he looks upon as consisting of leaves in close combination. His I’easons for considering the petals and stamens as homologous with leaves, are based upon the same facts as those which led Linnaeus, and, many years afterw-ards, Goethe, to the same conclusion. “In a word,” says Wolf, “we see nothing in the whole plant, wdiose parts at first sight differ so remarkably from each other, but leaves and stem, to which latter the root is referrible.” “ If,” he continues, “the organs of a plant, with the exception of the stalk, are thus referrible to the leaf, and are mere modifications of it, a theory, showing the manner in which plants are generated is obviously not a very difficult one to form, and at the same time the course is indicated which we must follow in propounding it. It must first be ascertained by observation in what way the ordinary leaves are formed, or in other words, how ordinary vegetation takes place; on what basis it rests, and by means of what powers it is brought into existence. Having gained this knowledge, we must investigate the causes which so modify the general mode of growth as to produce,'in the }ilace of leaves, the jiarts of the flower.” The basis of all these mollifications he attributes to a gradual diminution in the powers of vegetation. It may here ho remarked that during the interval between the juiblication of the ‘Theoria Generationis ’ and that of the essay in the St. Petersburg ‘ Transactions,’ to which reference has just been made, Wolf seems to have abandoned the notion that the stamens were buds peculiar to the corolline leavo.s, for in the latter essay he refers the stamens to leaves also; and it is worthy of notice that while the ‘Theoria Generationis was published one year before the ‘ Prolepsis Plautarum ’ of Linnaeus