Immature protophloem sieve elements present in the embryo of Phaseolus mungo mature at about the time of germination. The sieve elements differentiate both acropetally and basipetally. There are numerous protophloem sieve tubes in the upper hypocotyl. These are connected by anastomosis to four sieve tubes in the root. The protophloem Sieve tubes are accompanied by hyperchromatic phloem parenchyma. Hyperchromaticity is the greatest near the differentiating end in the root. Vascular bundles in the cotyledon are amphicribral. Thin deposits of callose are present in some sieve plates but absent in others.