Abstract: The present paper reports seed characters of 14 populations in Chinese Blyxa, examined using light microscope and scanning electron microscope. The internal structures of seeds were observed under light microscope after being prepared by paraffin section. The results show that differences between populations of different species are more distinct than between those within a species. The 14 populations in Chinese Blyxa are grouped into 4 species, i.e. Blyxa echinosperma (G. B. clarke) Hook. f., B. auberti Rich., B. leiosper-ma Koid., B. japonica (Miq.) Maxim.

Key words: Hydrocharitaceae, Blyxa, Seed characters