Which plant is known to have male and female flowers occurring on separate plants?

The plant known for having male and female flowers on separate plants is the common elodea. This is a characteristic of dioecious plants, where individual plants are distinctly male or female, each producing only one type of flower. In the case of common elodea, the presence of separate male and female individuals allows for the potential for outcrossing and genetic diversity within the population. Understanding the reproductive strategies of aquatic plants like common elodea is essential for effective management and control practices, particularly in the context of aquatic ecosystems, where such species may play significant roles in habitat structure and function.

Other plants listed have different reproductive strategies. For example, watergrass and Eurasian watermilfoil typically exhibit hermaphroditism or other forms of sexual reproduction that do not involve distinct male and female plants, while water smartweed may also display variability in reproductive structures but does not fit the characteristic of dioecy as distinctly as common elodea does. Hence, the correct identification of common elodea as a dioecious plant is crucial for understanding its ecological role and management in aquatic environments.