[Growth of nodule bacteria in soil]

As was found with the aid of capillary microscopy, the nodule bacteria of pea and lupine in soil are encountered as rods, bacteroids, and cocci. The rod-like cells form bacteroids not only in the nodules but also outside, in soil. The bacteroids are viable and later reproduce the coccoid cells (arthrospores). The rods and bacteroids prevail in soil during flowering of the legumes, and the cocci are predominant at the end of vegetation.