Note:  Do not rely on this information. It is very old.


Exine, the outer coat or exospore of the pollengrain (microspore) of flowering plants, formerly known as the extine. Smooth in the pollen of self-pollinating and wind-pollinated flowers, in insect or bird-pollinated ones it is often furnished with spinous (echinulate) or ridge-like projections. In Pinus it is produced into two reticulately-marked air-bladders. It is either simply burst or slashed to permit the protrusion of the pollen-tube in germination, or little lid-like portions of it may be pushed off.