The spores of nine taxa of Formosan Plagiogyria arc studied by scanning electron microscope. They are found to have trilcte spores of medium size (30-36 u X 38-65 u, in polar x equatorial diameters), mostly with rounded or hemispherical processes, and wilh raised laesurae having thin or thick raargos. Based upon sculptinc ornamentations five major types of spores can be discerned. A key to the taxa based on palynological data alone is given. Comparison with other species of Plagiogyria found elsewhere are also made. Possible use of spore characteristics in species differentiation and the course of the development of the perispore are discussed. Some outstanding potential of the inherent capacity of scanning electron microscope in palynological studies are pointed out.