Abstract
Chromosome numbers were reported in five species of Stemonaceae, i. e., Croomia heterosepala (2n=24), C. japonica (2n=24), Stemona japonica (2n=14), S. sessilifolia (2n=14) and S. tuberosa (2n=14). Karyotypes were also described in these species exclusive of S. tuberosa. In the classification of the centromeric position, C. heterosepala and C. japonica are identical to each other, but S. japonica and S. sessilifolia are slightly different. The present and earlier reports confirm that the three genera of Stemonaceae (s. str.) have different base number : x=12 in Croomia, x=7 in Stemona, and x=9 in Stichoneuron. With currently available phylogenetic hypotheses, the primitive base number of the family seems to be x=7.
