Abstract: Embryology of Potaninia mongolica is studied in this paper. The results firstly show that the mode of reproduction conforms to apospory. Three to seven aposporous archespores are developed from nucellar cells in chalazal end. The archespores increase and form uninuclear embryo sac, which undergoes three mitoses to form several eight-nucleated mature embryo sac as Hieracium type. But embryo is developed from only one embryo sac. Development of aposporous embryo sacs shows polarity, which extend from micropylar end to chalazal end. No normal sexuparous embryo sac is found.

Key words: apomixis, Embryology, apospory, Potaninia mongolica