The Stature and Chromosomes of Oenothera gigas, 
De Vries. 
By 
Regiuald Ruggles Gates, 
University of Chicago. 
With plates XXIX and XXX. 
Although the cytological studies upon this form are not yet com- 
plete, owing to lack of sufficient material, yet the results already 
obtained are believed to be of sufficient interest to warrant their 
publication at this time. A more extended study of this form will 
be made later, and in particular a more elaborate series of measure- 
ments will be undertaken, to extend the data presented liere. 
Among the mutants of Oenothera Lamarcläana thus far examined, 
all, with the exception of 0. gigas , have the same number of chro- 
mosomes as the parent form (14), with probably occasional departures 
of one from this number in certain individuals. In 0. gigas, however, 
the number of chromosomes in all individuals thus far examined is 
28 or 29. This doubling in the number of chromosomes implies 
that 0. gigas comes in a different category from all the other mu- 
tants whose chromosome count is known. 
The writer read a preliminary paper on 0. gigas before the 
Botanical Society of America in December 1907, and a brief abstract 
of this was published 1 ). From a study of the pollen mother cells 
the number of chromosomes was found to be 28. As stated else- 
where (Gates, 1908a), the materials for these counts were obtained 
from Mr. A. C. Life, who collected them from the 1905 Oenothera 
garden (from seeds of De Vries) at the Marine Biological Laboratory, 
Woods Holl, Mass. Miss Lutz, who afterwards took up the work 
Further studies on the chromosomes of Oenothera. Science 27 : 335. 
Feb. 28. 1908. 
Archiv f. Zellforschung. III. 
35 
