204 BOTANICAL GAZETTE [APRIL 
(figs. 7, 23, 44, 45). The cell plate forms late; it is most definite 
after the fibers have taken their final position (figs. 6, 7, 8, 
41, 45). These mitoses are similar to that described for Abies 
balsamea (9). : 
The cell plate is evidently associated with the formation of the 
cell wall. In fig. 45 the arched fibers remain only at one side, but 
here there is a distinct cell plate and the cell wall is curved outward 
to meet it. When the wall is formed the fibers disappear. In 
many cases no cell plate could be seen (figs. 5, 21, 22, 23), and the 
division in the cytoplasm is continuous with the end of the fibers 
(fig. 25). 
There is abundant evidence that the achromatic fibers are 
definite structures which change their position. The fact that 
there are groups of spindle fibers which have no immediate con- 
nection with nuclear membranes or chromosomes is further evi- 
dence for their individuality (fig. 8). 
Secondary divisions have markedly different characters. A 
polar cap is formed during prophase (fig. 48); the spindle fibers 
are more strongly developed during metaphase (fig. 38); the cell 
plate forms early (figs. 47, 49), and the spindle fibers retain their 
original positions. The similarity of secondary divisions in the 
first and third primary derivatives is illustrated by figs. 47 and 49. 
Chromatic extrusions 
In the early stages of the gametophyte, darkly staining bodies 
occur in the cytoplasm. When the primary nucleus is in the rest- 
ing stage, these bodies appear as spherical masses surrounded by 
a clearer area (fig. 34); when the primary cell is in active mitosis 
these extrusions become fragmented (fig. 35). These bodies 
originate from wandering chromosomes which escape during Mr 
tosis. Separate chromosomes are found near the primary cell wall 
during metaphase (fig. 36). Evidently these never take part In 
cell plate formation. They contract into spherical masses and 
wander into the cytoplasm. In other cases, during late anaphase, 
several chromosomes prematurely contract to form a more OF less 
compact mass, thereby separating themselves from the chrom0- 
somes which later undergo a similar change (fig. 3). 
