1. The inner layer of the exine, the rigid outer wall of a pollen grain or spore.
Usage: botany; technical

Examples

• The endexine provides structural support to the pollen grain.
• Palynologists examine the endexine to classify plant species.
• The thickness of the endexine varies among different pollen types.
• Under the electron microscope, the endexine appears as a distinct inner layer.
• The endexine is composed of sporopollenin, a resistant polymer.