342 BOTANICAL GAZETTE [MAY 
nucleus is largely due to its sudden expansion by an increase in 
the karyolymph. This involves. a sudden change in the karyo- 
plasmic relation, which is probably connected with the fact that, 
without further chromatic or cytoplasmic growth, two mitoses, 
one of which involves a segregation and the other a split of the 
chromosomes, take place in quick succession. 
Synapsis, therefore, has no special significance in the life cycle, 
but depends upon a temporary change in the karyoplasmic rela- 
tion, which is necessitated by the segregation process, intercalated 
between two mitoses, one of which (in plants) is sporophytic and 
the other gametophytic. 
Since the life cycle involves a pairing of homologous chromo- 
somes at the time of fertilization and their continued association 
in pairs until they are separated in the heterotypic mitosis, synap- 
sis is not the delayed and final act of fertilization, as frequently 
interpreted. Conceptions of synapsis as bringing about an inter- 
change of chromomeres or particles in the chromosomes are not 
supported by critical observations; and ideas involving an exchange 
of “influences” are rendered superfluous by the fact that the ho- 
mologous chromosomes are paired throughout the sporophyte. 
Reduction does not consist in a transverse or qualitative and 
a longitudinal or quantitative split of the chromosomes accord- 
ing to the conception of WEISMANN, but involves merely a segre- 
gation and redistribution of the members of homologous palts 
of whole somatic chromosomes. If the most widely accepted 
general account of reduction be universal, then a transverse seg” 
mentation of the chromosomes never regularly occurs. But ‘it 
may be for purely physical reasons that a somatic chromosome 
always splits longitudinally. It is not necessary to assume that 
the function of this split is to produce an equal division and dis- 
tribution of differentiated ‘‘ids”’ arranged along its axis. 
Missourt BoTranicat GARDEN 
Tt. Louts, Mo. 
