424 BOTANICAL GAZETTE [DECEMBER 
Very soon after the stage shown in fig. 7, a differentiation 
becomes apparent. A thick wall forms a sort of diaphragm 
between the definitely cellular and the free nuclear or loosely 
cellular portions of the proembryo (figs. 8,9, d). Just below the 
diaphragm the cells are large and with scanty protoplasmic con- 
tents, while one and in the middle two layers of cells are much 
smaller and have dense protoplasmic contents (fig. 8). This more 
deeply staining region at the tip becomes the embryo proper, while 
the large cells, in contact with the diaphragm, will differentiate 
into the suspensor. Long cells like a and 6 in fig. 8 may divide 
again, the outer cell then contributing to the suspensor, while the 
other forms a part of the “‘rosette’”’ and never gets beyond the 
original limits of the egg. The suspensor cells now divide both 
longitudinally and transversely, and it becomes difficult or impos- 
sible to distinguish any boundary between suspensor and embryo 
proper (fig. 9). As the periclines at the tip of this figure indicate, 
the dermatogen has not yet been differentiated. In both figs. 
8 and 9 the embryos have not yet pierced the egg membrane. 
The egg membrane now disorganizes, apparently becoming 
digested, and the rapidly elongating suspensor thrusts the embryo 
through the base of the egg into the endosperm. At this time 
mucilage ducts begin to appear in the suspensor (fig. 10). As soon 
as the embryos break through the egg membranes, the four or 
five or six suspensors become twisted together, and as one dissects 
them out they appear like a single suspensor with one embryo 
at the tip; but when they have reached a length of 1 cm., a careful 
examination with a pocket lens will show unsuccessful embryos 
at various distances from the egg region and a single embryo at 
the tip. I have never seen a suspensor branching, as described 
for Encephalartos by Saxton (9), but have seen unsuccessful - 
embryos which project somewhat from the general suspensor and 
so caused the appearance of branching. 
The suspensor is a remarkable feature of the od embryo. 
Its growth and twisting is accompanied by an extensive disorgan- 
ization of the endosperm in the archegonial region, especially just 
beneath the archegonia, so that there is formed a large cavity 
which becomes filled with the long suspensor. The cavity is moist, 
