Abstract:In order to understand the relationship of spore development with morphology of floral organ in Osmanthus fragrans, the changes in morphology of floret organ during micro- and megaspores development of ‘Zao Zi Yin’ bisexual plant were observed. The results show that the meiosis of microspore mother cell started when flower bud at ball-shaped stage suddenly expanded, and it came into tetrad stage at top bract stage. Majority of microspore tetrads were tetrahedral, minority were decussate, and others between the two ways. Flower bud was at the bud-pedicel stage, microspore develop to the late uninucleate stage, and flower bud from bud-eye stage to full blooming stage, microspore form 2-celled pollen and mature, the anther length increased from 0.3 mm to 1 mm, color changed from colorless transparent to bright yellow. Pistil stigma two lobed, ovary 2 rooms, each room 2 ovules, amphitropous ovule, unitegmic, tenuinucellate, and funicle was not obvious. During two-cell pollen period, the megaspore mother cell goes on meiosis to form megaspore. To flowering stage, the 8-nuclear sac was mature with polygonum type. The development of stamen was earlier than that of pistils, they tend to mature at the same time after flowering. So, the micro- and mega-sporogenesis had high relation with morphology of floret organs. It was suggested that the micro- and mega-spore development period could be judged according to morphological characters of floral organs.