Two complementary factors C and R for the production of flower colours have been found already by the former investigators. In plants lacking either any of them or both, the flower should be white in its corolla, though in the flower tubes or stems some white flowers may be coloured. The author could ascertain through several crossing experiments the genetic relation of composition and the colouration as follows:- CY……Colour-tubed white flower with green stem cR……Light yellow-tubed white flower with coloured stem cY……Light yell ow-tubed white flower with green stem The factor Cis connected to some extent with the colour of folower-tubes, and R with that of stems. The F1 plant derived from the crossing between Cr white type and cR white type almost always segregates out in the next generation the coloured and the whites containing three types on the ratio 9:7. The results obtained by crossing the normal coloured flower with the third type white was not reported in this paper, and in this case the coloured F1 plant was found to segregate the coloured and the whites on the same ratio as well as in the previous crossing, though the dihybrid ratio was somewhat disturbed on account of the occurrence of a coupling between the factor c and r. There occurs another white group having yellow tubes and green stems just like the third type white, but producing white seeds. This is due to the lacking of the factor Ca, which activates C.