156 BOTANICAL GAZETTE [SEPTEMBER 
is probable that all the fibers showing cell plate elements in jig 4 
are the original connecting fibers, while the peripheral fibers are 
the previously described radiating fibers. I have previously 
shown that the changes in the connecting fibers, before the for 
mation of the cell plate elements take place in all of the fibes 
at the same time, while the radiating fibers have apparentlys 
changed as to form peripheral connecting fibers. Whether all 
of the connecting fibers form cell plate elements was a poitl 
that I could not settle with certainty. It is possible that tho 
connecting fibers which did not show the changes described i® 
the preliminary stages do not form cell plate elements. The 
phenomena observed in later stages render such a possi ility 
more probable. | 
After they first become visible, the cell plate elements 
tinue to enlarge in their equatorial diameter until they come into 
contact with one another and fuse into a continuous plate. This 
process is accompanied by the further shortening of the fibers 
In connection with the shortening of the spindle fibers there 
a continued appearance of trophoplasm in the terminal parts 
the spindle (figs. 4, 5). ee 
The result of the processes just described may be brief 
summed up as follows. There is in the spindle a youn . 
plate formed simultaneously from the substance of the spi 4 
fibers. In the onion it lies in the midst of a zone of resent 
carbohydrate material to be used in the formation of the ae 
cellulose wall. In the larch such a zone is not seen : ol 
stage. The cell plate may now be said to begin the next st 
in its development. a 
3. The growing stage. poe 
mace 
This stage is marked by the following phenomen : 
central fibers continue to shorten, adding their substance net! 
cell plate until they have finally disappeared. The per ' 
fibers begin to appear more and more bent and to fo 
plate elements. As the central fibers disappear their eg 
partly taken by granular trophoplasm and the daught® 
come to lie nearer the young cell plate. While the Per 
