The discovery of the widespread occurrence of this mycorhizal symbiosis must be neld to be one of the most important results of research upon the nutritive processes of plants during the closing decade of the 19th century.
Each species of green plant may form a mycorhiza with two or three different Fungi, and a single species of Fungus may enter into symbiosis with several green plants.
This interesting case of symbiosis is equalled by yet another case.
The work of numerous observers has shown that the free nitrogen of the atmosphere is brought into combination in the soil in the nodules filled with bacteria on the roots of Leguminosae, and since these nodules are the morphological expression of a symbiosis between the higher plant and the bacteria, there is evidently here a case similar to the last.
Symbiosis: Marshall Ward, " Symbiosis," Ann.