436 Tvicotyloiis Races. 



plants of these groups and the result in the following 

 spring, 1898, was 23 to 65%, with a mean of 40% among 

 17 seed-parents, and 26 to 75%, with a mean of 47%, 

 amongst 13. 



Phacclia tanacetifolia, Fig. 87. My race arose from 

 the same set of bought seed which included Clarkia, Hcli- 

 chrysuui and Papaver. In the summer of 1895 I had 

 20 tricotylous plants, raised from bought seed, in flower. 

 Their values constituted a two-fold group like that which 

 occurred in Papaver, Three seed-parents had 12 — 12 

 and 14%, but the rest had values between 1 and 10%; 

 the three former were alone used as the basis of my 

 race. The three cultures derived from them gave 30 — 6 

 and 9 separate harvests, which were evaluated in the 

 spring of 1897 in the usual way. The lowest, middle 

 and highest values for the three groups were 5 — 26 — 58, 

 21—28—42, and 6—14 — 16%. Obviously the two first 

 grand-parents had given better offspring than the last 

 one. I selected the former group for the continuation 

 of the race, employing the two best plants with 54 and 

 58%. They gave two groups of tricotylous plants, the 

 harvests from which exhibited a great advance on the 

 average, but which did not differ essentially from one 

 another. With the exception of the extremes these fig- 

 ures constituted a closely circumscribed group of 35 val- 

 ues distributed between 35 and 72%, with a mean of 

 57%. 



The extremes were 20 and 22%, and on the other 

 side 80 — 85 and 90%. The two former figures, which 

 were probably the result of incomplete isolation, occurred 

 in the same group. The higher figures, however, were 

 distributed over the offspring of both grandparents. 



Obviously the mean value of 57% of the intermediate 



