The morphology and systematics of the pollen of Stellaria

Pollen morphology of 64 species and five varieties of the genus Stellaria L. was studied using scanning electron microscopy and compared with that of Myosoton Moench. Of these, 60 species and four varieties were reported for the first time. Pollen grains of genus Stellaria are spheroidal or spheroidal-polyhedral, pantoporate and 21.36–38.38 μm in size, and have 10–22 prominent or sunken apertures uniformly distributed on their surface. Granules are present on the opercules of all species except for S. uchiyamana. The surface ornamentation of Stellaria pollen grains is of the microechinate-perforate type, microechinate-punctate type or microechinate-punctate-perforate type. The exceptional morphological similarity of Stellaria and Myosoton supports the combination of the genus Myosoton with the genus Stellaria.