534 
STRUCTURE AND LIFE HISTORIES 
Lamarckiana their cordate character. I call this form 
O. lavifolia." 
"When I first discovered them (1887) they were repre- 
sented by very few individuals. Moreover each form 
occupied a particular spot on the field. O. brevistylis 
occurred quite close to the base from which the OEnothera 
FIG. 400. A plant of the evening-primrose (CEnolhera biennis) which, 
by "bud sporting," has given rise (at the left) to a branch having the 
characters of another species. 
had spread; O. l&vifolia on the other hand, in a small 
group of i o to 12 plants, some of which were flowering 
whilst others consisted only of radical leaves, in a part of 
the field which had not up to that time been occupied by 
O. Lamarckiana. The impression produced was that all 
these plants had come from the seeds of a single mutant. 
Since that time, both the new forms have more or less 
spread over the field" (de Vries). 
