Chapters in modern botany / by Patrick Geddes.

  • Geddes, Patrick, Sir, 1854-1932.
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Chapters in modern botany / by Patrick Geddes. Source: Wellcome Collection.

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    and similar cases. But precise knowledge of the meaning of this partnership was not attained till 1874, when Belt, the naturalist of Nicaragua, and Delpino, an Italian botanist, cleared up the whole matter. Let us quote Belt's account 1 of his discovery : The thorns of the bull's- horn Acacia are hollow, and are tenanted by ants that make a small hole for their entrance and e.\it near one end of the thorn, and also burrow through the partition that separates the two horns, so that one entrance serves for both. Here they rear their young, and in the wet season every one of the thorns is tenanted, and hundreds of ants are to be seen running about, especially over the younger leaves. If one of them be touched, or a branch shaken, the little ants (Pseiidomyr7na bicolor) swarm out from the hollow thorns, and attack the aggressor with jaws and sting. They sting severely, raising a little white lump that does not disappear in less than twenty-four hours. They form a most efficient standing army for the plant, which prevents not only the mammalia from browsing on the leaves, but delivers it from the attacks of a much more dangerous enemy—the leaf-cutting ant. For these services the ants are not only securely housed by the plant, but are provided with a bountiful supply of food, and to secure their attendance at the right time and place, the food is so arranged and distributed as to effect that object with wonderful perfection. There is a sweet gland at the base of each pair of leaflets on the bipinnate leaf, and a little yellow pear-like body at the end of each small division of the compound leaf which is carried off when ripe. The young thorns are soft and filled with sweet pulp, so that the ant finds its house full of food. As it hollows this out, the thorn increases in size and bulges out towards the base. 1 The Naturalist in Nicaragua. Lond. 1874.