Stem anatomy, stomataltypes and stomatal index in addition the morphological charactersfor 6 species of genusAmaranthus named A.caudatus, A. graecizens A. hybridus, A. retroflexus, A. spinosusand A.viridisare collected from Jazan, Saudi Arabia.Two types of stomata are recognized; anomocytic and anisocytic. Anomocytic type found only in A. graecizens while anisocytic found in the remaider. The different stem anatomical characters are discussed and revealed a distinct characters for each species.Both Leaf epidermal and anatomical features revealed a great taxononmical values which in turn will used for the correct identification of each species. An artificial key is provided for the identification of the studied species.