Abstract: The minor leaf vein of Populus deltoides Bartr. cv. ’Lux’ (ex. I-69/55), and P. ×euramericana (Dode) Guinier cv. ’San Martino’ (ex. I-72/58) has no A-type and B-type transfer cells, which exist in the herb dicotyledon. But some structures like compound plasmodesma and paramural body that vary morphologically with the development of the leaf can be produced by the companion cells and the phloem parechyma cells of the minor leaf vein. It’s shown that their occurrence has something to do with the frequent local transport. The sieve tube members in the minor leaf vein are differentiated through the formation of the P-protein body, the function of the lysosome in the vacuome and the secretion of the dictyosome. In the two clones of the Aegeiros poplar, i.e., I-69 and I-72 there exist distinctions. It seems that the distinctions are related to the increment. Therefore, they require further research.