Vegetable Teratology. Maxwell T. Masters

Vegetable Teratology - Maxwell T. Masters


Скачать книгу
have met with four perfect leaves at the summit of the ovary, in the place usually occupied by the sepals. This would also favour the notion that the axis entered into the constitution of the fruit in this genus.

      Mr. B. Clarke, in his 'New Arrangement of Phanerogamous Plants,' p. 4, cites a case wherein the perianth was completely detached from the surface of the ovary in Cannabis sativa.

      The very singular mode of germination of Sechium edule in which the fruit, instead of rotting, becomes thickened into a kind of rhizome or tuber, is a fact that should not be overlooked in investigating the true nature of the fruit in this order.

      

      The following are the genera in which the change has been most frequently observed:

       *Rosa!

       *Pyrus!

       *Cratægus!

       *Daucus!

       Pastinaca.

       Torilis.

       Apium.

       Œnanthe!

       Heracleum,

       Athamanta.

       Selinum.

       Carum.

       Imperatoria.

       Rudbeckia!

       *Campanula!

       Lonicera!

       Cucumis!

       Cannabis.

      Solution of the stamens from the petals.—A separation of the stamens from the petals in flowers, wherein those organs are usually adherent one to the other does not often occur unattended by other changes. It has been observed in Cobæa scandens (Turpin), in Antirrhinum majus, and in many double flowers.

      FOOTNOTES:

       Table of Contents

      [85] 'Gard. Chron.,' 1865, p. 554; 1867, p. 599.

      [86] 'Bull. Soc. Bot. Fr.' 1854, p. 303.

       ALTERATIONS OF POSITION.

       Table of Contents

      Necessarily connected with changes in the arrangement of organs are similar alterations in their position; so closely, indeed, that but for convenience sake, it would be unnecessary to treat them separately. There are, however, some anomalous developments affecting the relative position of organs that could hardly be treated of under any of the preceding paragraphs. There are, also, certain rare instances where an organ is not so much displaced as misplaced; that is to say, it is developed on or from a portion of the plant, which under usual circumstances does not produce such an organ. In the former instance, the altered position is due to or coexistent with other changes, but in the latter case the new growth may spring from organs otherwise in nowise different from ordinary. The word Displacement is here used to signify the unusual position of an organ; while Heterotaxy may serve to include those cases where a new growth makes its appearance in an unwonted situation, as, for instance, a leaf-bud on a root, &c. Prolification is also included under this heading, the unusual position of the buds in these cases being of graver import than the mere increase in number. Alterations in the position of the sexual organs are spoken of under the head of Heterogamy.

      CHAPTER I.

       DISPLACEMENT.

      Real or apparent displacement of organs from their usual position is an almost necessary consequence of, or is, at least, coexistent with a large number of teratological phenomena. It is obvious that abnormal unions or disunions, suppressions, hypertrophies, &c., are very liable to bring about or to be accompanied with changes in the position, either of the parts directly affected or of adjoining organs.

      In this place, then, it is merely necessary to allude to some of the more important displacements, and to refer for further details to the sections relating to those irregularities of growth on which the displacement depends.

      Of somewhat different nature to those above described was an anomaly described by M. Gay at a meeting of the Botanical Society of France, April 8th, 1859. The plant affected was Leucoium æstivum, and the changes observed were apparently attributable to a simple separation of two leaves that are usually contiguous. "Suppose," says M. Gay in describing this malformation, "the first leaf of the terminal bud separated by a long internode from the other leaves, which remain closely packed; and further, suppose an evident thickening of the upper portion of the lengthened internode, and there will be not only a single bulb, bearing with the leaves of the present year all the remnants of the leaves of the two preceding years, but two bulbs placed one above another, on the same axis, separated by the length of the internode."

      Fig. 39.—Unusual position of bulbs of tulip;


Скачать книгу