CELL DIVISION BY FURROWING IN MAGNOLIA 
Maneval (13), nor Guignard (8) suggests even the possibility of the 
presence of such a structure. That it is in some instances formed can- 
not be doubted, as is shown by the photomicrograph (fig. 3) and the 
drawing (fig. 20) below. It is never seen to extend the entire distance 
across the mother cell, but in one or two instances the nuclei were 
closer to one side than to the other, and the orange zone reached the 
membrane on that side; in a few cases it was found to be interrupted, 
though this may have been caused by the shock of fixation. Cells in 
later stages can all be easily detected by the fact that the nuclei at the 
time of the presence of the orange zone are very flat and near together; 
whereas upon the disappearance of this body the nuclei round up and 
separate. Juel shows incomplete cell plates in Hemerocallis (10) and 
Carex (11), in the latter of which the cell plates are ephemeral. The 
case of Magnolia is shghtly different, for it is not the cell plate which 
is ephemeral here, but rather the orange zone. Furthermore, in Mag- 
nolia the disappearance of this equatorial structure is followed by 
furrowing, which is not the case in the forms studied by Juel. 
After the disappearance of the orange zone the nuclei enlarge and 
in them the nucleoli appear (figs. 4 and 21). The latter are at first 
small and there may be one or more of them in each nucleus, but they 
usually enlarge up to the time of the second division, keeping pace with 
the enlargement of the nucleus and even exceeding the latter in some 
instances. In fact, a nucleolus may become so large at times that it 
extends from the polar to the equatorial side of the nucleus (fig. 8). 
All except the large nucleoli are perfectly spherical. The latter often 
appear bell-shaped, like the starch grains of ginger. In addition to 
one or two large nucleoli in each nucleus at this stage there are also 
some small ones. A surprisingly large number of these cells in inter- 
kinesis have the large nucleoli exactly opposite each other in the nuclei 
of the same mother cell (figs. 6 and 21), though they may be in the 
center or at either side. Large nucleoli were found opposite each 
other in 59 cells, while in only 5 were they otherwise arranged. 
While the nucleoli are enlarging, the furrow makes its appearance. 
It is difficult to arrange a series of stages in nuclear changes and furrow 
formation during interkinesis. However, the initiation of furrow 
formation is reasonably well indicated by nuclear phenomena. After 
the orange zone has disappeared the nuclei slowly enlarge and pull 
apart (fig. 5), becoming more nearly spherical (fig. 6). Before they 
attain the maximum distance apart the spireme has become completely 
