1gt2| PFEIFFER—LEITNERIA 193 
showed a single sporogenous cell and two parietal cells (fig. 4), 
which evidently arose by the periclinal division of the primary 
parietal cell. The further division of the parietal cells continued 
steadily, so that within four weeks there were often more than 10 
parietal cells lying between the sporogenous cell and the epidermis 
fig. 5). Very often a periclinal division of the epidermal cells of 
the nucellus occurred (fig. 5). The time when the mother cell 
went into synapsis varied greatly, some of the ovules showing this 
condition as early as February 16 (fig. 5), while others showed the 
mother cell in a presynaptic condition as late as March 22. How- 
ever, at this later date the majority of mother cells were in synapsis. 
Although the division of the megaspore mother cell was not 
observed, it evidently gave rise to a linear tetrad of megaspores. 
Above the micropylar end of the young embryo sac there were 
often three deeply stained masses (fig. 6), which had the same 
appearance as recognized abortive megaspores in other forms. 
As the embryo sac developed, the further periclinal and anti- 
clinal divisions of the parietal tissue continued, so that when the 
sac was ready for fertilization there were often as many as 30 
layers of cells lying above it. Very often the tip of the nucellus 
developed into a somewhat slender beak, which took the form of 
the more or less twisted integuments (fig. 3). 
The female gametophyte 
After the formation of the row of megaspores, the innermost 
or functional spore immediately began division. In material col- 
lected on March 21 and killed on March 25 the embryo sacs were 
practically all in the four-celled stage. The two-celled stage 
‘figured (fig. 6) was of material killed on March 25 of the preceding 
year. It would seem that the embryo sac remained in the four- 
celled stage for some time, since material killed on March 30, April 
3, and April 5 showed practically all the sacs in this condition. An 
ovule killed in the afternoon of April 5 showed the simultaneous 
division of these four nuclei to form the light nuclei of the completed 
sac. 
In the mature embryo sac the egg has the usual organization, 
with the vacuole toward the micropylar end, but the synergids 
