Abstract:The results of pollen morphology of water lily could provide evidence for the phylogenetic evolution of Nymphaea and the selection of parents for hybrid breeding. In this study, the pollen morphology of 18 species or variety in Nymphaea were observed by scanning electron microscopy, and the morphological characteristics of pollen were measured and analyzed. At the same time, the pollen viability of the N. ‘Peter Slocum’ was measured by in vitro germination method. The results showed that the pollen of 18 species or variety in Nymphaea were all single grains, and the morphology was nearly spheroid or oblate spheroid. Among them, the pollen grains of N. gigantea were the largest, and the pollen grains of N. lotus were the smallest. According to the cluster analysis, the 18 species or variety of Nymphaea were divided into four subgenera, among which the Nymphaea and Brachyceras were most closely related. The pollen germination rate of N. ‘Peter Slocum’ is more than 95%. The pollen morphological characteristics of Nymphaea, especially the pollen germination furrow type and the outer wall decoration, can provide key evidence for the classification of species, the relationship between subgenera and species, and the phylogenetic law of Nymphaea.