360 



HANS AND OLOF TEDIN 



5,5o/9,89 = 0,56. In cross IV the 9 class may be calculated as low, the 

 10 class as high number of internodes. Then segregation occurs in 

 93 : 25, corresponding to an expected segregation in 88,5 : 29,5 and 

 D/m = 4,5/4,74 = 0,95. Hence it is certain that in those two crosses 

 a factor, in the following called Sn, has been involved, which in its 

 dominant state increases the number of sterile nodes below the first 

 flower. The two crosses being between quite different parents there 

 is no certainty that it is the same factor that in both crosses controls 



the number of sterile nodes, but until more is known about the matter, 

 there is no use introducing more than one factor into the factorial 

 formula of Pisiim. 



In crosses I + II there is a faint minimum in the 12 class, but it 

 is impossible to know how to calculate the individuals in this and the 

 neighbouring classes. The place of the minimum, however, indicates 

 monohybrid segregation in this cross, too. The different mode of 

 segregation in crosses I + II and III is with certainty due to the diffe- 

 rent years in which the Fois are grown. 



The mode of inheritance of sterile nodes is far from being analy- 

 sed by the statement of monohybrid segregation in two or three 

 cases. No account is given for the occurrence of pure lilies with 



