A plant that does not produce flowers is called a non-flowering plant or a gymnosperm. These plants reproduce through seeds or spores rather than flowers. Gymnosperms include conifers, cycads, and ginkgoes, while another group, ferns, represent non-flowering vascular plants that reproduce through spores. Non-flowering plants are essential in various ecosystems, providing habitats and resources for wildlife. They play crucial roles in photosynthesis, carbon sequestration, and soil stabilization.