Rensselaer Republican, Volume 17, Number 24, Rensselaer, Jasper County, 19 February 1885 — LEAVES. [ARTICLE]

LEAVES.

And Why They Fell. These withered glories of the summer, their fall in the sere and yellow state of autumn, are symbolic. There are. vivid and nbisy pleasures; there are those of the quiet kind, and not the less pleasing, even perhaps more cherished in memory when tinctured with some sadness. And in such a mood have I watched, on a still, calm day in latter-autumn, when no breath of wind was stirring, the leaves settling straight down in silent, tremulous fall, “one after one,” } suggesting and recalling the friends and loved ones that had successively passed away in peace. Yet it is not altogether surcease, and loss; the leaf-fall, better understood, may suggest brighter associations. The poet, indeed, expresses, in his gifted strain, the common thought which associates the phenomena of the fall of the leaf with the transitory tenure of all life, —the inevitable course of youth to maturity and decrepit age, of uplifted waving greenness and freshness to the sere and withered return to earth and dust. Ask a friend why the leaves fall in autumn. He will answer “they fall because they die.” * * * The phenomena of defoliation are compared by my old friend Loudon with the sloughing of dead parts, —a state initiated in the leaf “by the cold of au.tumn, and accelerated by the frosts of winter.” And such may still be the common notion; it was long my own. But some summers ago I was led to think a little closer of the matter by an effect of a thunderstorm which took place in July. The lightning struck a tall elm tree, one branch of which it killed. The leaves became brown and died; but they did not fall. When autumn came their bright brethren, fading to a similar tint, fell. When winter frost had set in, and the crisp snow overspread the park like a gigantic bride cake, the elm was all stripped save the thunder-striken branch, and the only leaves that remained were those that had been killed in midsummer. They were never* shed; they rotted off bit by bit. This led me to examine the nature of the attachment of some leaves in some trees in my own garden. The expanded base of the petiole, or leaf stock, is attached by continuity of woody tissues, including parenchymal cells, sap-vessels, air-ves-sels, ana the cutioule of the bark continued from the branch into the stalk. The plane and sycamore are good subjects for the examination. Soon a delicate line of the cuticle indicates the coming place of separation; soon also in the sycamore, and most of our deciduous trees, a tiny bud peeps from the axil, or angle between the leaf-stalk and stem. Now, next, I may remark, that, watching the autumnal period of the fall, I observed,that defoliation was accelerated not so much by early frost as by unusual warm and open weather in November, and then, especially with the plane-tree, that many of the leaves which naturally fell were not in the “sere and yellow” state, but were green, as full life. Even now you may see the difference of color between such leaf shed when living, which I hold in my right hand, and the ordinary withered leaf in my left. My examination at this period led me to perceive that the immediate cause or stimulus of the fall was the growth of the baby-bud at the base of the leaf-stalk, which, pressing on the tissues of that part, caused their disintegration and disappearance in a manner aiihlogous to that of “absorption” in the animal economy. Pursu ing the examination in different kinds of deciduous trees, I found that the mother-leaf was pushed off in different ways, and that these represented the different ways in which deciduous teeth are displaced by their successors. Thus, in the plane tree the bud pushes vertically up the middle of the base of the stalk, while in the sycamore it excavates obliquely the side of the base. The shed plane leaf shows a conical cavity at the detached part of the petiole, like that at the base of a shed tooth of the crocodle; the fallen sycamore leaf shows an oblique lateral depression, like that at the base of the shed tooth of lizard. In the plane tree the central part of the parenchymal cells attaching the stalk are first, pressed, and successively yield to the growing bud, the disintegrating process spreading to the periphery, not along a transverse, but a conical surface;’ although, by a sort of sympathy, the epidermis, ere the killing process reaches it, indicates the line of coming solution of continuity. The leaf stalk may for a while be supported by, being sheathed upon, the bud, after it has been wholly separated from its stein; and the pro-, cess of thia separation provides against any rupture or “bleeding” from sapvessels. Nothing can show greater contrast than the separated surface of a leaf stalk thus orderly detached and that of one violently torn off Mild weather accelerating the bud growth, pushes off the leaf before its time; early frost, checking the bud growth, may turn the color of the leaf, but delays the fall. Young leaves killed by vernal frosts rot off, but are not shed entire. The autumnal fall of the leaf, then, occurs not i because one leaf dies, but because another leaf is born; it is a phenomenon that may be associated with perennial and every springing life, rather than with decay and death. It is a process, therefore, which if it naturally at first excites sentiments of sadness, may and ought, when rightly understood, to call up a cheerful and grateful sense to the power that provides ample compensation for seeming loss. — Prof. Owen.