Tricotylous Half Races. 
387 
of 1892 I obtained only a single hemi-tricotyl from about 
20,000 bought seeds. The seeds of this plant gave rise 
in 1893 to live tricotyls and two hemi-tricotyls among 
4000 seedlings, that is, about 02%. Their seeds were 
harvested separately, and as the expectation of tricotyls 
was a small one, great quantities of it were sown, 
recorded from 800 to 2900 from each, i. e., altogether 
about 15,000 seedlings, and 
found the ratio of tricotyls 
(and hemi-tricotyls) to be 
from 0.2 to 0.4%. It did not, 
therefore, seem justified to 
make a selection among the 
individual seed-parents. In 
1894, 12 tricotyls the stems of 
which had remained ternary, 
and twelve specimens with 
normal decussate stems were 
planted out. Several beauti- 
ful fasciations and occasional 
cases of spiral torsion oc- 
curred in this culture (p. 369) . 
The seeds were harvested sep- 
arately. In the spring of 1895 
they again produced only 
from 0.1 to 0.4% of tricotyls. 
Seventeen specimens from the 
seed pans with from 0.2 to 0.4% were planted out about 
a meter apart, but the seeds produced, in 1896, scarcely 
any tricotyls and only from five seed-parents, the pro- 
portion being from 0.3 to 0.7%. 
In the course of four generations selection had, there- 
fore, brought about practically no advance. 
Fig. 82. Dracocephalum rnol- 
davicum. A whole plant. 
