Page:Popular Science Monthly Volume 2.djvu/302

From Wikisource
Jump to navigation Jump to search
This page has been validated.

hole and insert its point into a second one. Mr. Darwin has seen a tendril keep its point, in one instance, for twenty hours, and, in another instance, for thirty-six hours, in a minute hole, and then withdraw it. After the record of this fact on such unexceptional evidence, we are the more prepared to credit the statement of Mr. Anderson-Henry, that a climber will, in running up a wall, carefully avoid contact with another climber which it dislikes; and even the account by M. Paul Lévy,[1] that the lianes of tropical forests have an affinity for certain trees, toward which they direct their growth, and not toward those nearest to them; carefully drawing themselves away when they encounter one of the objectionable trees.

We may conclude our account of climbing plants with the following remarks by Mr. Darwin: "It has often been vaguely asserted that plants are distinguished from animals by not having the power of movement. It should rather be said that plants acquire and display this power only when it is of some advantage to them, but that this is of comparatively rare occurrence, as they are affixed to the ground, and food is brought to them by the wind and rain. We see how high in the scale of organization a plant may rise, when we look at one of the more perfect tendril-bearers. It first places its tendrils ready for action, as a polypus places its tentacula. If the tendril be displaced, it is acted on by the force of gravity, and rights itself. It is acted on

Fig. 5.
PSM V02 D302 Mimosa pudica.jpg

by the light, and bends toward or from it, or disregards it, whichever may be most advantageous. During several days the tendrils or internodes, or both, spontaneously revolve with a steady motion. The tendril strikes some object, and quickly curls round, and firmly grasps

  1. Bulletin de la Societé Botanique de France. Translated in the Gardener's Chronicle, March 19, 1870.