In this study,somatic chromosomes were counted and karyotypes were determined in 13 plants from a population of Allium macrostemon Bunge.(1)Three were heptaploid with karyotype 2n=7x=46m(2SAT)+10sm(2SAT) and 2B karyotype of stebbins,ten were tetraploid with 2n=4x=26m(1SAT)+6sm(1SAT) and 2B karyotype.Mixoploidy and heptaploid were reported for the first time.(2)It can be inferred that the heptaploid plants was produced via an unreduced gamete of the triploid united with an unreduced gamete of the tetraploid.The number of satellites does not match the ploidy of plants and satellites are not necessarily attached to homologues.The infraspecific ploidy increase is consistent with species evolution,the higher ploidy,the more advanced population.