Fixation of Nitrogen in Two African Species of Myrica

Summary By means ofgrowth experiments and 15N tests on whole plants and their parts, it is shown that the root nodules present on Myrica cordifolia and M. pilulifera fix atmospheric nitrogen to an extent which suffices to sustain good growth of the plants in a rooting medium free of combined nitrogen. Thus the nodules have the same properties and physiological significance as the nodules of M. gale and M. cerifera. The possession of this internal source of combined nitrogen doubtless explains in part the ability of M. cordifolia to flourish on sand dunes.