74 
ANNE M. LUTZ 
seed pans in January. De Vries ('15a) and Davis ('15a) have em- 
phasized this fact recently and have suggested means of greatly 
increasing the percentage of germinations. . . we can not feel 
confident," Davis states ('15&), " that the records of any cultures of 
Oenothera so far reported are complete for their possible progeny. 
The percentages calculated for 'mutants' and the ratios of classes in 
breeding experiments can not be accepted as final in exact genetical 
work. We are not in a position even to guess what may be the changes 
of front when exact data become available." It is clear that future 
records of cultures, to be of value, must show that they are complete 
for their possible progeny. 
As a rule, seeds are obtained in greater abundance from 14-chromosome 
forms selfed, or pollinated by other 14-chromosome forms of the same, or 
'different species, than from 14 -{--chromosome forms selfed, or pollinated 
'by other 14 -{--chromosome plants of the same, or different species, — par- 
iicularly if the 14 -{--chromosome individuals have more than 14, but fewer 
than 28, chromosomes. 
Beginning with the summer of 1908, I adopted the practice of 
counting all seeds sown; of planting seeds at spaced intervals in seed 
pans, and of recording the germinations. Only in a few instances have 
these precautions been neglected. The results have clearly shown 
that when seeds not more than one year old are sown in pans of steri- 
lized soil in January and kept under ordinary greenhouse conditions, 
usually larger percentages of germinations are secured within the first 
four or five months from seeds of 14-chromosome plants selfed, or polli- 
nated by other 14-chromosome plants of the same, or different species, 
than from 14 -{--chromosome plants selfed, or pollinated by other i4-{-- 
chromosome plants of the same, or different species — particularly if the 
1 4 -{--chromosome individuals have more than 14, but fewer than 28, 
chromosomes. Hence it appears that the number of seeds produced by 
a form and the ability of the seeds to germinate, at least within the time 
limits specified, are factors which are associated with the chromosome 
number of the plant, or numbers of the plants, producing them. The 
ability of a seed to germinate appears to depend, not wholly, but to a certain 
extent, upon the number of chromosomes which it bears, and, possibly, 
in accordance with Gates's suggestion (15a, p. 194), upon the compati- 
bility, or incompatibility of the chromosomal combination which the 
number represents. It also appears that the ability of a seed to ger- 
minate is directly associated with its own chromosome number and only 
