Morphological characters on the leaf nectar gland of Korean Prunus 4 species and 1 form were observed by SM. The results were summarized as follows ; The shapes of nectar gland on the plane figure were two, the circular and the irregular ovate. The species of circulr shape were P. maackii, P. maximowiczii, P. sargentii and P. yedoensis. The irregular ovate shape was only one species, P. pendula for. ascendens. The shapes of nectar gland on the side figure were the reentrant apices and the rounded. The reentrant apices were two shapes. First, the species of the center reentrant was three, P. madckii, P. sargentii and P. yedoensis . Seconei, the species of the irregular reentrant was P. pendula for. ascendens. The rounded apex was only one species, P. mazimotuiczii . Especially on the P. pendula for, ascendens, the upheaval situation on surface of leaf blade was due to the sinking of reverse part of leaf blade at the nectar gland. The point of this abnormal shape was well distinguished from the other species. On the frequency by the part of leaf with nectar gland, the species to be observed only at the leaf base was P. pendula for. aseendens, the other species was observed two part of leaf base and petioles. In this study, some Prunus species were well keyed out on the basis of the morphological characters of leaf nectar gland.