Plant-life, with 74 full-page illus., 24 being from photos, by the author and 50 in colour from drawings . o spines. This is a purely physio-logical adaptation to desert conditions, but it happensto have an important secondary use, for browsinganimals would need to be sore distressed by hunger andthirst before they would attempt to satisfy their appe-tite at the expense of sore and irritated mouths. Thesedesert plants survive because they have evolved a formwhich is doubly useful; it conserves the water-supply,and at the same time keeps animals at bay. Kerner, in his Natural History of Plants,
Plant-life, with 74 full-page illus., 24 being from photos, by the author and 50 in colour from drawings . o spines. This is a purely physio-logical adaptation to desert conditions, but it happensto have an important secondary use, for browsinganimals would need to be sore distressed by hunger andthirst before they would attempt to satisfy their appe-tite at the expense of sore and irritated mouths. Thesedesert plants survive because they have evolved a formwhich is doubly useful; it conserves the water-supply,and at the same time keeps animals at bay. Kerner, in his Natural History of Plants, directs atten-tion to the manner in which young trees of Beeches,Oaks, and Larches, if they grow where they can bereached by oxen, sheep, and goats, have their youngshoots and the attached leaves eaten by these happens that the portion of a shoot left on the treeafter its mutilation dries up, but its hinder part remainsalive. One effect of the pruning by these animals is avigorous production of buds on the living part. Shootsarise from these buds next spring, and the pruning by Plate ~> YELLOW ARCHANGEL (Lamkim galeobdolon),Order LABIAT/E. DEFENCES OF PLANTS 347 animals may be repeated with similar results. Afterrepeated prunings the tree has the appearance of agarden tree that has been pruned into some conven-tional shape. But after some years of pruning, thetime comes when animals leave the tree alone. Thetips of the mutilated shoots which become dry andhard are eventually so crowded, and the branches be-come so thick and sturdy, that a grazing animal attempt-ing to reach young leaves pushes its nose against hardpoints that hurt in a tender spot. This is a suggestiveissue. The aggressor against a defenceless tree un-consciously causes the eventual appearance of a de-fensive armour, which renders the tree immune tofurther attack. Beech hedges that are regularly pruneddevelop armour of the same description. Many plants find safe refuge under hedges and tre
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1915
