Greenhouse and plant growth room experiments showed that shading of plants had no appreciable effect on the vegetatively active fungi colonizing the primary roots of wheat and soybean seedlings growing in fertile, disease-free soil. Although marked differences in plant development were obvious, the general pattern of root colonization was essentially the same for the two levels of illumination used. The results suggest that the saprophytic fungi which normally colonize the roots of healthy plants may also colonize roots of abnormal plants providing that the soil is relatively free from plant pathogenic forms.Species ofPhomaaccounted for a much higher proportion of the isolates from wheat roots than from soybean roots, whereas the majority of cultures from soybeans proved to be species ofFusarium.