Observations on the nature, longevity and size of trees / by Alexander Harvey.

  • Harvey, Alexander, 1811-1889.
Date:
[1847]
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the nature, longevity and size of trees / by Alexander Harvey. Source: Wellcome Collection.

    18/24 (page 16)
    posing this to be the case, would by no means take from them the character of entire and perfect plants, if it could be shewn that the office of roots is otherwise adequately pro¬ vided for. And, with reference to the latter, it may be ob¬ served, that the fact of a structure entering into their con¬ stitution, not existing in other plants, would not at all affect their claim to be so regarded, particularly if it could be shewn that that structure is required to meet some condition of their existence peculiar to themselves, or to serve some ulterior purpose in the economy of nature. And the woody layer, it is to be remembered, is strictly an annual formation, and so far accords with the view taken of the growths in question as being annual plants. Now, the structure referred to—the woody layer—clearly subserves, immediately, the purpose of a mechanical support to the growths or plants of the same year’s formation with it¬ self, and remotely that of producing timber. Without it trees could scarcely grow at all, or, if they could, would be of little use to man. But it serves also the office of roots to those growths or plants, being the channel by which the nutritive matters in the soil are conveyed upwards to the growing stems, and leaves, and flowers. And if it thus serves these various purposes, the questions stated must be regarded as satisfactorily disposed of. The only question will be, whether the woody layer, in its origin and mode of formation, be actually of the nature of, or rather identical with, roots, amd only secondarily intended for a mechanical support, and for the production of timber; or whether it is truly a special formation for the accomplishment of these latter objects, and only virtually of the nature of roots 1 After what has been stated, however, this other question is of no real practical importance in relation to our present inquiry. The woody layer may be formed in the manner that M. Du Petit Thouars supposes, or in that insisted on by M. Mirbel and others. If in the former, it constitutes true roots, and is nothing more than “ a mass of roots if in the latter, it is only virtually roots. The mode of its forma- ^ Ui’ Lindley, Introduction to Botany, First Edition, ]). 245.