1c6 BOTANICAL GAZETTE [FEBRUARY 
experiments fertilization is as easily accomplished as with pure 
O. Lamarckiana pollen; which increases the probability that no 
extensive deterioration of pollen grains occurs. POHL (22) states, 
however, that only about 70 per cent. of the pollen grains of O. 
Lamarckiana are perfect. Whether the deterioration is selective is 
of course not known. 
The fact that the heterochromosomes originate from the spirem 
by the cutting off of a portion of its length after synapsis, and later 
degenerate, suggests that in this manner a portion of the chromatin 
is dispensed with in certain pollen mother cells, while in others where 
heterochromosomes do not occur it is all retained. Those who hold 
strictly to the individuality of the chromosomes, and that they repre- 
sent in some way certain specific characters or groups of characters, 
would probably maintain that by this means the specific characters 
represented by the discarded chromatin are lost. Lm1iE (15) 
expresses the view (which he strongly substantiates) that the chromo- 
somes can represent only general characters belonging to the organism 
as a whole; such as color, stature, pubescence, etc. These would 
appear to correspond with the unit characters of DEVRIES, at least 
in many essentials, for instances of the latter as cited by DEVRIES in 
the Oenotheras are pigment (in O. rubrinervis), stature (O. nanella is 
a dwarf), and pubescence. This loss of chromatin in the germ cells 
might then appear to be a method of dispensing with certain unit 
characters of the organism. A great amount of additional work 
will be required, however, in the study of somatic characters in connec- 
tion with chromosome morphology, before it will be possible to 
correlate these two categories of structure, if such a correlation exists. 
ROSENBERG (25) has recently published a further paper on the 
Drosera hybrid, in which he finds that occasionally two pollen grains 
of a tetrad have the characters of one parent and two those of the 
other parent, the supposition being that this is preceded by segrega- 
tion of the maternal and paternal chromosomes in the first reduction 
division. This may be considered a proof that the segregation of 
parental characters when it occurs takes place during the reduction 
divisions. In the light of such facts it seems highly probable that 
mutations in the Oenotheras will be found to originate during the 
