. Cyclopedia of farm crops, a popular survey of crops and crop-making methods in the United States and Canada;. Farm produce; Agriculture. LEGUMES LESPEDEZA 395 biosis, a living together. The term is now gener- ally applied to those cases of symbiosis where there is a mutual benefit to the symbionts. This special kind of symbiosis is often called mutualistic or reciprocal symbiosis to distinguish it from those cases of symbiosis existing between a strict para- site and its host, which is called antagonistic sym- biosis. 'Disjunctive symbiosis has reference to the relation of flowers and insect
. Cyclopedia of farm crops, a popular survey of crops and crop-making methods in the United States and Canada;. Farm produce; Agriculture. LEGUMES LESPEDEZA 395 biosis, a living together. The term is now gener- ally applied to those cases of symbiosis where there is a mutual benefit to the symbionts. This special kind of symbiosis is often called mutualistic or reciprocal symbiosis to distinguish it from those cases of symbiosis existing between a strict para- site and its host, which is called antagonistic sym- biosis. 'Disjunctive symbiosis has reference to the relation of flowers and insects in pollination, while contact symbiosis has reference to the relation between the bacterium, Glostrydium pasteurianum, and certain low, blue-green algae in the soil, the algse supplying the bacterium with carbohydrates. These carbohydrates supply the Glostrydium with the energy which enables it to assimilate free nitrogen. Some have raised an objection against the use of the term symbiosis applied to the relation of the nodule bacterium and the legume, on the ground that the bacterium is a parasite, that certain cells in the tubercle are destroyed, and that it is difiicult to see what benefit the host can derive from an association with a parasite which destroys some of its cells. It is beyond contradiction, however, that leguminous plants do benefit from this association, in the fixed nitrogen which they are able to absorb from the dead bacteroids in the nodule, except perhaps in soils already rich in nitrogenous plant- food, under which condition it is known that few nodules are formed, while in soils poor in nitroge- nous plant-foods many nodules are formed and the legume profits to a great extent from the symbiosis. The parasitism is confined to the nodular roots or mycorhiza. This nodule serves a useful purpose for the legume, and the fact that its formation is caused by a parasite, and that some of its cells die, does not necessarily lead to the conclusion that the legu
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