428 Tricot \lous 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 70% 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 indicates a satisfac- 
tory advance. 
Mercunalis annua. In 1892 I possessed two tricotyl- 
ous plants, one a female, the other a male, which 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 3134 4152 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 with 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 was 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 
