428 Tricol\Ious Races. 



In 1897 I continued the culture for the purpose of 

 improving the race. I sowed the seeds of four plants 

 which had 65 — 66 — 67 nd 707© tricotyls, and managed 

 to bring 60 tricotylous plants to maturity, of which 26 

 set seed. Their hereditary values varied between 35 and 

 90%, their mean being 74%. This mdicates a satisfac- 

 tory advance. 



Mercurial is annua. In 1892 I possessed two tricotyl- 

 ous plants, one a female, the other a male, wdiich had 

 been raised from species that had been obtained in ex- 

 change from some botanical garden. The yield was very 

 poor; only 14 seeds germinated and they had two cotyl- 

 edons each (1893). In saving their seeds I did not 

 isolate them and found 2% tricotyls amongst the 1100 

 seedlings which were raised in the following spring 

 (1894). Besides these several tricotyls had come up in 

 the bed from seeds which had fallen out, so that I had 

 altogether 18 female and a corresponding number of 

 male tricotyls. This culture gave the expected result. 

 The hereditary values calculated for the individual seed- 

 parents were distributed regularly between 1 and 55%, 

 the five highest being 31—34—41—52 and 55%. The 

 intermediate race had therefore been isolated at least in 

 these latter specimens. In 1895 I only planted out tri- 

 cotylous seedlings from the one parent Avith 55%. Of 

 course it was uncertain in this case whether the pollen 

 had been produced by plants belonging to the intermediate 

 race. But the values calculated in the spring of 1896 

 suggested that the race w^as fairly pure. I have already 

 given this series of figures above (p. 423). The mean 

 was at 67, the maximum had increased to 86%. 



In 1896 the tricotyls of two parents, whose values 

 were 78 and 81%, were planted out in lots of 25 and 20 



