pollen sac

A chamber in which *pollen grains (microspores) are formed in the angiosperms and gymnosperms. It is homologous with the *microsporangia of the pteridophytes. In angiosperms there are usually four pollen sacs in an anther, arranged in two lobes, either side of the connective tissue. In the conifers there   may   be   numerous   pollen   sacs formed on microphylls in the axils of the male strobilus. Compare ovule. See also stamen.