40 THE BOTANICAL MAGAZINE. CVoi. xxxvi. No. 423. 



Resume of the Original Article in Japanese. 



Yoshitaka Imai :— Genetic Studies in Morning Glories. VI. 



In the 3rd report of the author's studies in morning glories, the 

 genetic aspect of the flower-colors of two races of Ph. purpurea, 

 W. D. (white double flowered) and R. S. (red single flowered), were 

 fully described. Another race denoted by W. S., bearing white single 

 flower, was crossed with these two races cited above, and raising 

 the progeny of the hybrids the genetic relationships of them were 

 analized as may be represented by the following constitutions : — 



R. S RRSSUUdd 



W. D , RRssuuDD 



W. S rrSSUUdd 



The allelomorphs given above are considered as having the effects 

 as follows :— 



R.r r is responsible to white flower with green stem and the 



colored condition in both flower and stem is caused by R. 

 The heterozygotic flower is intermediate in color. 



S.S The factor S makes both flower-and stem-color dilute, 



while in the presence of S the color become more intense. 

 The effect of both foctors can only become visible in the 

 presence of R. Biotypes resulted by the interaction of these 

 two allelomorphic pairs are : — 



RS intense flowered series with intensely colored stem. 



Rs faint flowered series with dilute stem. 



rS _ 



::= white flower with green stem. 



r Br— "" 



U.U In the presence of U five colored spots are formed in the 



rays of corolla leaving the other parts colorless. The 

 heterozygotic flower is intermediately colored. In the co- 

 operation of u and S, both in double doses, apparently 

 white flower with dilute stem is formed. 



D.d D is responsible to the dilution of flower-color. 



