The Isolation of Tricotylous Intermediate Races. 417 



each (1899). This year 77 plants gave a sufficient har- 

 vest, the figures for the three groups (each derived from 

 a single grandparent) did not exhibit any differences 

 worth mentioning. The minimum was 2^/c, the mean 

 12, and the highest value 25%. Therefore a consider- 

 able advance on the preceding generation had taken place. 

 In 1900 I had only 31 plants, bearing seed, which were 

 cultivated in the same way as in the previous year. They 

 constituted three groups, each from a single grandparent, 

 but without exhibiting any differences worth considera- 

 tion. The hereditary values varied between 5 and 17% 

 and their mean was 10 to 13%. The culture of the last 

 year (1901) embraced 40 plants, the values of which 

 varied between and 21 and had a mean of 10%. 



The result, like that of the two foregoing species, 

 may now be summarized in tabular form. 



VALUES DETERMINED IN THE FOLLOWING 



The prospect of raising an intermediate race seems 

 therefore in this experiment to be as small as in Amaran- 

 tus and Scrophularia. 



§ 6. THE ISOLATION OF TRICOTYLOUS INTERMEDIATE 



RACES. 



It is just as easy to isolate an intermediate race from 

 seed which has been bought or obtained from any other 

 source if it happens to be already present in it, as it is 



