WHITE— STUDIES OF INHERITANCE IN PISUM. 555 



presence of B by giving purple flowers in F^ in crosses with the pinks. 

 Tschermak and Lock, however, have obtained true breeding white- 

 flowered segregates lacking this factor. 



When the necessary factors for axil color and dotted seed 

 coats are present together with_ A, these respective regions are red 

 pigmented, which if B is added, are modified to purple. In the light 

 of the present genetic data, then, varieties of peas in respect to flower 

 color have the following formulas : 



Purple flowers AABB 



Pink flowers AAbb 



White flowers aaBB 



White flowers (segregates only) aabb 



10. Time of Flowering. 



Varieties of peas vary from about 35 to 150 days or more in the 

 time it takes them to reach the flowering period from the date of 

 planting, when all are planted the same day and grown under similar 

 conditions. As might be expected, different varieties of peas react 

 somewhat differently to changes in environment as regards the 

 time it takes them to reach the blooming period. Grown in 10 cm. 

 pots in the greenhouse in the winter time this period is considerably 

 lengthened in several varieties, while with other varieties there is 

 practically no change — the same length of time being required as 

 in the field cultures. Between the earliest and the latest blooming 

 varieties, there is a continuous range of varieties with blooming 

 periods at most not more than four days apart, so that in a random 

 collection of a hundred varieties, one might record another variety 

 in bloom almost every day. Between the individuals of a variety 

 such as are many of the dwarfs, the individual variation in time of 

 flowering is small, ranging over three to four days. Among the 

 so-called " half dwarfs " and tall varieties, individual variation 

 within the variety has a much wider range. Dwarfness, although 

 generally associated with earliness, is also associated with medium 

 late blooming varieties, but tall varieties are but very rarely early 

 bloomers. 



Lock (54), Tschermak (85) and Hoshino (40.5) have each 



