408 
Tricotylous Races. 
one that occurs. The form with coarsely dissected 
* 
leaves rounded at the base, and small flowers and fruits, 
is the one employed in my experiments (Fig. 84). In 
the summer of 1901 I planted out large numbers of both 
types in my garden, after a close examination of their 
characters. Both are, as far as my experience extends, 
quite constant for many gen- 
erations, i. e., they are good 
subspecies. 
My culture began in 1890 
with the seeds of a tricotylous 
plant from our botanical gar- 
den, which, in the following 
year, produced, besides a num- 
ber of atavists, four plants with 
three cotyledons and a main 
stem with ternary whorls up to 
the inflorescence (1891). From 
the seeds of one of these plants 
I again obtained in the summer 
of 1892 some tricotylous seed- 
lings, the majority of which, 
how r ever, became decussate af- 
terwards. Only two of them 
remained ternary throughout 
the summer, and these were the 
only ones which I allowed to 
flower. Among their seed I counted 780 and 1000 seed- 
lings respectively, and found the value in each case to 
be 1%. 
In 1893, 16 tricotylous plants flowered and constituted 
the fourth generation of my race. Their seeds were 
saved separately and produced a mean of from 1 to 2%, 
Fig. 84. Scrophularia nodosa. 
Main stem of the tricotyl- 
ons half race with ternary 
whorls of leaves. 
