1. Plural of exine; the outer layer of the wall of a pollen grain or spore.
Usage: botany; technical

Examples

• The exines of different plant species vary greatly in texture and ornamentation.
• Botanists examine exines under a microscope to identify pollen types.
• The thickness of exines can help distinguish between related plant species.
• Fossilized exines provide evidence of ancient plant life.
• Pollen grains with thick exines are more resistant to degradation.