When a plant species has male flowers on one plant and female flowers on another plant, the species is

• A. Monoecious
• B. Dioecious
• C. Ornamental
• D. Complete

Answer: (B)

Dioecious plants have male flowers on one plant and female flowers on another, meaning individuals are exclusively one sex. In this setup, pollination must occur between plants of opposite sexes in order to set fruit. This differs from monoecious species, where a single plant bears both male and female flowers. The terms ornamental or complete don’t describe this pattern of having separate-sex plants—ornamental refers to decorative use, and complete refers to whether a flower has all floral parts. For example, holly plants are dioecious: only the female plants bear berries, requiring pollen from a male plant nearby.