260 BOTANICAL GAZETTE [OCTOBER 
The remaining 4-7. and 3 per cent were mostly of the Lamarck- 
tana type, with some mutants belonging to albida, oblonga, and 
nanella. I had saved the fruits and their seeds in 7 or 8 groups, 
beginning at the base of the spike, and sown the seeds separately. 
But, just as in the previous case, there were no appreciable differ- 
ences in the percentage figures between the higher and the lower 
groups.. 
The main result is that the percentage of specimens of the 
cana type, which runs 15-60 per cent on annual individuals, 
may iticrease to 93-97 per cent on very vigorous biennial plants. 
It is thus clearly seen to be dependent upon the method of culti- 
vation. Obviously this rule may be applied to the percentages of 
O. scintillans, as previously discussed, and to those of O. pallescens 
and the other new dimorphic mutants to be described in this article. 
Oenothera Lamarckiana mut. pallescens (fig. 3).—Among all 
the mutants which arose in my garden from O. Lamarckiana, this 
form most closely resembles the parent type. In early stages the 
rosettes are the same, and in springtime, when still in the boxes, 
I have not as yet succeeded in distinguishing them. It is not 
until about 6 weeks after planting out on the beds that the differ- 
entiating marks begin to show (fig. 4). In the middle of June the 
leaves are clearly shorter, and the blade is set off from the narrowly- 
winged petiole by a sharp indentation. This character causes the 
rosettes to be more open because the petioles hardly touch one 
another. 
This spatulate form of the leaves remains, for a long time, the 
best mark of the race; but when the stem grows up, the whole 
plant is much more slender than the parent form (fig. 3). The 
stem is thin and low; in July, when the first flowers open, it often 
reaches only 75 cm., when the corresponding specimens of Lamarck- 
tana are already 1 m. and more in height. After a time, however, 
this difference disappears, since the spike is more elongated. It 
is less dense than in Lamarckiana; the bracts are much shorter and 
strikingly broader; the flower buds are large and conical, the 
flowers somewhat smaller, although still larger than those of 
O. biennis; the pollen is abundant and the fruits are short and thick, 
containing a good supply of seed. The foliage is of the same green 
