Pollen morphology of Chinese Pseudostellaria (Caryophyllaceae) and its systematic significance

Using light and scanning electron microscopy, we studied the pollen morphology of six species (one of which are endemic) of Chinese Pseudostellaria. All species were studied for the first time. Results of this study indicated that pollen grains of Pseudostellaria are spheroidal or spheroidal-polyhedral in shape and small or medium in size and pantoporate. Each pollen grain has 12-16 round pores. These pores are apart from each other by 5.77-7.73 μm and each has 7-13 granules in the operculum region. These features have important taxonomic significance. In addition, their pollen grains have thin exine with microechinate-punctate-perforate surface ornamentation. Pollen features do not support the traditional infrageneric classification of Pseudostellaria into two sections, but support that Pseudostellaria is closely related to other species of the Odontostemma clade.