408 



Tricotylo us Races. 



one that occurs. The form with coarselv 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, 

 however, 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- 

 ous half race with ternary 

 whorls of leaves. 



