In this study the anatomical features of mungbean and cowpea plants were used as a taxonomic evidence to justify the assignment of mungbean plant to the genus Vigna rather than to the genus Phaseolus. Both mungbean and cowpea plants are similar in the following anatomical characters:                 The roots have a tetrarch protostele. The stem outline is comprised of six ridges alternating with similar number of furrows. The vascular bundles are arranged in a ring of six large size collateral bundles located opposite to the ridges, in addition to some minor bundles in between. The pith comprises the stem core. The secondary growth takes place in nearly a continuous cylindrical form. Leaves are dorsiventral. Palisade tissue consists of 2-3 layers. Stomata are of paracytic type. The midrib is convex at both sides. Petiole is pentagonal in outline with two lateral wings at the corners of the adaxial side. Flower, fruit, and seed structures are identical.                 Phytochemical, morphological and anatomical evidences given in this 3-parts study suggest the acceptance of the scientific name: Vigna radiata (L.) Wilczek for mungbean plant.