Why are date palm referred to as dioecious?

Date palm is a dioecious species with male and female flowers being produced in clusters on separate palms. These flowering clusters are produced with axils of leaves of the previous year's growth. In rare cases both pistillate and staminate flowers are produced on the same spike while the presence of hermaphrodite flowers in the inflorescence has also been reported (Mason, 1915; Milne, 1918). Palms which carry both unisexual and hermaphrodite flowers are known as polygamous.