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.

    19/24 (page 17)
    tion, however, and its precise character, is unimportant. Still, if it is genuine roots, as M. Thouars maintains, and as Dr Lindley and Dr Carpenter agree with him in believing,^ it will at once follow that the growths in question have roots, and that having these, they have no extraneous element entering into their composition. And a positive and very valuable fact will be added to the general body of evidence already adduced in support of the view, that those growths possess the character ascribed to them. II. Secondly, at the close of every year, the annual growths or plants, with the exception, of course, of the newly-formed buds, cease to be, and never afterwards become, the seat of any vital action, i. e., they die, and never afterwards live. This is sufficiently obvious as regards the leaves and flowers, which wither, fall off, and completely disappear. It is equally true, however, of what remains of the other parts of the plants, ^. e., of the roots and the woody stems or shoots. But on what grounds are we entitled to say that these parts then die, and never again live '? 1. In the first place, because after the fall of the leaves, and during subsequent years, no growth or increase of the organic matter composing them takes place, as should be exhibited in an increase of their length and thickness, and produced in the way that the leaflet of spring is gradually developed into the full grown leaf of summer. They appear, indeed, to elongate and become thicker, i. e., to grow in length and breadth. This growth, however, is not a real extension of the parts in question, as it is in the leaflet; it is a new and independent formation at their extremities, and either around or within them, and may, by examination, be seen to be quite distinct from them,| being, in fact, the roots and * “ The most consistent account of its development is that given by Du Petit Thouars, who, followed by Lindley, regards the fibrous [woody] tissue as formed in the leaves, and growing downwards into the cambium, just as roots are pro¬ longed into the soil. This view would liken the woody fibres to the roots of the buds; and such a comparison, though at first sight improbable, is fully borne out by facts.”—Carpenter, PWnciipZes of General and Comparative Physiology, 1st Ed., p. 278. t Lindley, Op. cit., p. 228 and p. 241, et seq.