The wall surrounding this substance has an intine 
The wall surrounding this substance has an intine [IN-teen] layer and a sculptured exine [EK-seen] layer. This substance is not used by ferns, and this is produced in structures called microsporangia [my-kroe-spoe-RAN-jee-uh]. Brownian motion was discovered by observing these grains in water. These cells often start on an anther at the end of a stamen [STAY-men] and are transported to a pistil. Name these grains containing microspores that are transported by wind or bees to fertilize many plants.
The wall surrounding this substance has an intine [IN-teen] layer and a sculptured exine [EK-seen] layer.
pollen (accept spores before "ferns")