The Movements and Habits of Climbing Plants.

1891. London: William Clowes and Sons for John Murray, 1891. 8vo. Original green cloth gilt; pp. x + 208 + 32 (ads.), wood-engraved illustrations in the text after George Darwin; previous owner's signature to prelim, partially uncut, very good. Second edition, fifth thousand. Darwin's investigation of the adaptive value of climbing plants was originally issued in the Journal and Proceedings of the Linnean Society of London in 1865 and was only published in book form in 1875 in its second edition, which greatly enlarged the original work of 118 pages to 208 pages. Darwin "found that `climbing' is a result of the process of nutation; the apex of the plant's stem bends to one side while it grows and the plane of the bend itself revolves, clockwise or counterclockwise, so that the apex describes circular sweeping movements. In the hop plant -- in hot weather, during daylight hours -- it takes a little over two hours for each revolution. If the growing stem hits nothing, it continues to circle; if it hits an object it wraps itself around it by twining. Twining thus enables a young and feeble plant, in one season, to raise its growing point and leaves much higher from the ground, with more exposure to sunlight and air, without expending time and energy in the synthesis of woody supporting tissues. There is a further delicate adaptation here; a twining plant will not twine around an object larger than approximately six inches in diameter. This adaptation prevents it from climbing up a large tree, where it would be deprived of air and sun by the tree's own leaves" (DSB III, p. 575). Darwin continued these researches further after publication through his investigations into the mechanics of the bending of a plant's stem, which were published in The Power of Movement in Plants in 1880. Freeman 846.