Gymnosperms are primarily distinguished by their reproductive structures, specifically the presence of naked seeds that are not enclosed within an ovary. Unlike flowering plants (angiosperms), which produce seeds within a fruit, gymnosperms such as pines, firs, and cycads bear seeds on the surface of cones. This unique characteristic is a key aspect of their reproductive strategy.
The development of naked seeds allows gymnosperms to adapt to a variety of environments, often thriving in conditions where angiosperms may struggle. Additionally, gymnosperms typically exhibit other features such as needle-like leaves and a woody stem structure. Their ability to reproduce in harsher climates contributes to their longevity as one of the oldest groups of plants on Earth.