262 BOTANICAL GAZETTE [OCTOBER 
color as in the parent form, but much more crinkled and uneven, 
not as gray as in O. cana, nor as hairy as in this form. 
The impossibility of distinguishing the young plants before 
planting out evidently makes this mutant less fit for the determi- 
nation of splitting percent- 
‘ ages, because the sorting 
and counting has to be 
done on the beds. In my 
experiments I have always 
counted the individuals of 
the two types at the begin- 
ning of the flowering 
period, since at this time 
the limits between the two 
groups are the most sharp. 
Moreover, this simi- 
larity between the mutant 
and the parent species 
must diminish the chances 
of discovering mutant 
specimens of the new type. 
This is probably the reason 
why it was not observed 
before r1o11. Since that 
year new mutants of the 
: pallescens type have more 
Fic. 4.—Oenothera Lamarckiana mut. pal- . 
lescens: 3 5 ty pical leaves of the rosette of radical than once arisen from O. 
leaves; June 16, 1914. Lamarckiana and from 
some of its derivatives, 
especially in 1914. All of these mutants exactly resembled the 
first one in their whole structure and in all their marks. 
I have made pedigree cultures of the offspring of my first three 
mutants. These arose from seed of the same parent plant of 
1909, which belonged to the second generation of a guarded strain 
of O. Lamarckiana, derived from a rosette collected in 1905 in the 
original field near Hilversum. One part of this seed was sown in 
1910 and yielded, among about 500 specimens, 1 pallescens, together 
with 1 rubrinervis, 3 oblonga, 2 lata, 1 scintillans, 1 nanella, the 
