Exine

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exine

[′ek‚sēn]
(botany)

Exine

 

(also exosporium), in seed plants, the outer layer of the wall of pollen grains (microspores). In many plants the outside of the exine has nodules or reticular enlargements, which form specific patterns characteristic of a particular species and are there fore often used to identify the species to which a pollen grain belongs.