THE ORGANIZATION OF THE NUCLEI IN THE ROOT 
TIPS OF PODOPHYLLUM PELTATUM 
JAMES BERTRAM OVERTON 
Introduction 
Although the nuclear divisions of somatic cells have been fre¬ 
quently studied and the somatic chromosomes during certain stages 
of division have received a great deal of attention, a thorough 
study of their structure and behavior during rest has until re¬ 
cently been largely neglected. Thus far the structure and rela¬ 
tion of the chromosomes during rest has been determined in com¬ 
paratively few forms. A number of valuable papers have ap¬ 
peared on this phase of the subject, notably those of van Wisse- 
lingh (’99), Gregoire (’03, ’06, ’08, ’12) and his students, Haecker 
(’04, ’07), Sijpkens (’04), Strasburger (’05), Bonnevie (’08), 
Nemec ’99, ’10), Digby (’10, ’19), Fraser and Snell (’ll), Lun- 
degard (’10a, b, ’12 b, c.), von Schustow (’13), Sharp (’13, ’20a), 
and others, so that a general interest in the subject has greatly 
increased 
The opinions held by some cytologists, especially those of the 
English school, that in both diploid and haploid nuclei a separa¬ 
tion of the chromosomes into two equivalent portions on the spindle 
is already foreshadowed by their fission in the preceding telo¬ 
phase, as well as the interpretation of Dehorne (’ll) and others 
that the chromosomes are in all stages of division associated in 
pairs, each chromosome having the value of a longitudinally split 
chromosome, have increased interest in the subject of somatic 
mitosis. 
The observations described in the following paper are the out¬ 
come of several years of investigation and thought upon the 
structure and organization of the nuclei in the root tips of Po¬ 
dophyllum pelt at um, the result of which have already been briefly 
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