Microspore Cells Small 289×320 Medium 578×640 Large 925×1024 Download Tiff Original 2168×2400 | (547.0 KB) Description The primary sporogenous cell (ps) and the primary parietal layer (ppr) in the stages of "formation of anthers and pollen grains or microspores of Silphium." -Stevens, 1916 Keywords anthers, microspore formation, microspores, plant anatomy, plant cells, pollen grains, primary parietal layer, primary sporogenous cell, Silphium Galleries Cellular Botany Source: William Chase Stevens Plant Anatomy (Philadelphia, PA: P. Blakiston, 1916)