(1) The characteristics af the autotetraploid of Abelmoschus Malcihot induced by colchicine treatment are reported. (2) Treating with of 0.1% solution 288 seedlings of " Hiroshima-Zairaishu " and 353 such of " Akagukishu ", 2 plant of 4x in appearance were obtained in the latter variety. (3) By the external form, the size of stomata and pollen grains of each plants of 2 Iines in next generation, the chromosome doubling was tentatively judged. (4) Chromosome numbers in root tips of 2 lines of 4x were both 2n=136 and that of 2x was 2n = 68. (5) Compairing 4 x plants with 2 x, the height is taller or smaller in different individuals, the size of stomata and pollen grains larger, the % of abortive pollen grains higher, the pod fruited only in the end season and its number smaller, the length of pod shorter though its diameter rather larger, the number of seeds per pod considerablly smaller, its size larger, the germination and flowering time somewhat later, and the viscosity of fluid contained in the root almost the same, but some individuals show the higher viscosity.
