I. Leitch 191 



ficant that the intermediates in this case proved to be M, indicating 

 that the same disturbance is operating here. 



In*1917 the extremes from row 3 were sown, and as they give a 

 typical example of the method of segregation, the chart of these plants 

 has been chosen to illustrate the method. The curves for row 3 and 

 other typical forms are also given. The constant X, row 45, was con- 

 tinued in the four rows 27, 28, 29 and 30 in 1917, and as 28 and 30 

 showed each one plant with beans of unusual length these two plants, 

 with two short variates, were continued in 1918. The curves for these, 

 31, 33 (short) and 32, 34 (long), show at once that the aberration was 

 without significance and that here again the X line breeds true. 



The other rows segregate as before, giving X, M and a type that 

 again splits. 



In group 14 a similar disturbance appears in that, of the two 

 apparently X types chosen as seed in 1915, one bred true and the 

 other proved to belong to the segregating type. One E type chosen 

 proved as before heterozygous. Three doubtful intermediate types were 

 selected, and, of these, two, as in gi'oup 5, proved to be M while the 

 third proved to be entirely different. It gave rise to a group of plants 

 occupying a position similar to that of the parent plant, and like the 

 9 group already mentioned intermediate between E and M. Continued 

 in 1917 this intermediate group, 6, shows a more scattered distribution 

 but little or no evidence of segregation. To test the point, the extreme 

 short variates (2) and longest (1) in row 37 were chosen as seed, the 

 shortest and longest, at the same time unusually narrow, from row 39 

 and the two longest from 35. The two short 37s give rows 35 and 36 

 respectively in 1918 and the long variate, row 57. Both chart and 

 curves show that there is no difference between them ; indeed the 

 curve of lengths for 57 lies, if anything, slightly to the left of those 

 for 35 and 36. As regards the two rows selected from 39, 18 (the 

 aberrant type) and 37 (the short), there is admittedly a slight differ- 

 ence. But the range of 18 is characteristic for the more diffuse types 

 in this group, and 37 corresponds closely to the other rows just dealt 

 with. 18 shows no trace whatever of the unusual breadth of its parent 

 seed in 1917. It must therefore be concluded that there is no evidence 

 of segregation in this group. Group 6 belongs to a non-segregating type 

 intermediate between the original lines E and M. 



The same behaviour is found throughout the group 9. From the 

 1915 material were chosen seven plants for seed, including those with 

 the shortest and the longest seed. The general result was a group. 



