Pollen observation of wild Fragaria species native to China using SEM

China has some of the most diverse wild strawberry species of the world. In this study, pollen ultrastructure of 46 samples of wild strawberry native to China including seven diploid species and two new diploid genotypes were observed. A scanning electron microscope was used to investigate pollen characteristics and consider how they contribute to the classification of Fragaria species. The results showed that the pollen of the samples were prolate and tri-colporate. Pollen apertures were equally spaced along the polar axis and almost extended to the poles. The pollen size was similar and the pollen exine ornamentation had regular stripes approximately parallel to the polar axis. The depth of pollen exine ornamentation differed among different Fragaria species. Among the seven diploid species and two new diploid genotypes, F. nilgerrensis Schlect. had the deepest stripes of pollen exine ornamentation. F. nubicola Lindl., F. pentaphylla Lozinsk., and two new diploid genotypes had shallowest stripes, and F. vesca L., F. viridis Duch., F. chinensis Lozinsk. and F. mandschurica Staudt. were intermediate. Cluster analysis of typical pollen morphological characters showed that the results were similar to traditional species classification.