186 BOTANICAL GAZETTE [SEPTEMBER 
daughter nucleus is formed entirely from the chromosomes and the 
karyolymph in which they float. This is to mea strong observational 
evidence of chromosome continuity. 
Unlike Lawson’s description for Passiflora coerulea, the chromo- 
somes in Oenothera certainly do not fuse in the telophase of the 
heterotypic mitosis, but maintain their separate identity completely 
at first, and usually more or less completely thoughout the period of 
interkinesis. Occasionally stages are found which indicate that they 
string out and anastomose to some extent during a late stage of 
interkinesis, partly losing their sharp boundaries, but this stage 
apparently does not very often occur. 
Nucleoli may be formed de novo in these daughter nuclei, as I 
have described previously (8, p. 93). The chromosomes in this 
telophase are all clearly bivalents, in which the halves are closely in 
contact. I have examined thousands of nuclei in this stage and 
have never seen the halves other than more or less closely in contact. 
On the other hand, it is universally true in my observations that no 
two chromosome bivalents are ever found in contact. Not only is 
this the case, but they are invariably distributed at approximately 
equal distances from each other, just within the nuclear membrane. 
I have never seen an exception to this in any Oenothera studied. 
The position of the chromosomes might be explained by supposing 
that they are attached to the nuclear membrane from the first, and 
are thus carried outward as the nucleus grows.5 In many cases the 
chromosomes appear actually to be attached to the nuclear membrane, 
or at least to be lying very closely against it. This, however, leaves 
unexplained the fact that the chromosomes are never in contact with 
each other at this time, and further that they are very generally 
placed at approximately equal distances from each other, just within 
the nuclear wall. All these facts point to the supposition that the 
sIt might also be supposed that in the dehydration. processes prepaid : 
m 
mounting, the chromosomes would be drawn against the nuclear me 
in such a case one would undoubtedly find the chromosomes occasionally massed 
one side of the nucleus or irregularly placed, instead of being always at regular inte 
vals about the periphery. _ From the regularity of their placing I have no doubt fis 
the chromosomes occupy their original positions within the nucleus, and there is ° 
indication that they are ever disturbed by the processes of fixation, imbedding, ee 
staining, when properly carried out. ; 
TN 
