Abstract: Abstract The present paper deals with the karyotype study of 6 biotypes of Poncirus. The karyotypes consist of 6 pairs of median and 3 pairs of submedian constructions, belonging to "2A" type of Stebbins symmetry, and show infinitely small differences each biotype. It is worthy of note that the satellites show a certain degree of difference in size, though the positions of a pair of satellite are identical. The origin of large satellite is discussed.

Key words: Poncirus