Which type of plants are characterized by having seeds not enclosed by an ovary wall?

Gymnosperms are indeed characterized by having seeds that are not enclosed by an ovary wall. This group of plants includes conifers, cycads, Ginkgo, and gnetophytes. In gymnosperms, seeds typically develop on the surface of scales or leaves, rather than being enclosed in a fruit like in angiosperms. This distinctive feature is significant because it influences the reproductive strategies and ecological adaptations of gymnosperms compared to other plant groups.

For example, while angiosperms (flowering plants) have seeds that are protected within fruits, allowing for a diverse range of dispersal strategies and protection mechanisms, gymnosperms rely more on dispersal through wind or animals to carry their seeds away from the parent plant. The exposure of seeds directly on cones or other structures makes them generally less protected than those of flowering plants. Understanding this key distinction helps clarify the evolutionary relationship between these types of plants and their adaptations to various environments.