Abstract: Globular-shaped embryoids and embryonic Callus were simultaneously derived from the 7 to 8-week-old ovules of ponkan mandarin (Citrus reticulata Blanco), cultured on MT medium supplemented with 500 mg/L casein hydrolysate. During subculturing, callus morphogenesis can be carried out via somatic embryogenesis and organogenesis simultaneously. The processes and morphological characters of normal, abnormal and secondary somatic embryogenesis as well as organogenesis were systematically observed under SEM. The morphological basis of distinguishing between embryoid and adventitious bud in dicotyledons under SEM. was also produced.

Key words: Citrus, Ovule culture, Somatic embryogenesis, Organogenesis