Why do gymnosperms lack vessels?

Gymnosperms lack vessels in their xylem, unlike angiosperms, which have them. This difference in vascular structure is due to evolutionary divergence. Gymnosperms are an ancient group of plants that evolved before angiosperms (flowering plants). Their xylem lacks vessels because they evolved before the development of vessel elements.

Instead of vessels, gymnosperms have tracheids in their xylem. Tracheids are elongated cells with tapered ends that overlap, allowing water to move through pits in their walls. While tracheids are efficient at conducting water, they are not as specialized for efficient water transport as vessels.

The absence of vessels in gymnosperms is thought to be an adaptation to their environments and lifestyles at the time of their evolution. Despite the lack of vessels, gymnosperms are still able to thrive in various habitats, demonstrating the effectiveness of tracheids in water transport.