60 BOTANICAL GAZETTE [JANUARY 
quadrant stage (fig. 1), the endosperm contains at least 32 nuclei, 
held in the thin peripheral layer of cytoplasm. The nucellus at 
this stage is principally in the lower half of the ovulary cavity. A 
single layer, however, differing markedly from the rest, extends 
1 
Fics. 1-3.—Fig. 1, longitudinal median section of ovule, showing the embryo in 
the quadrant stage and the endosperm in the free nuclear condition; the cells of the 
outer layer of the nucellus and the inner layer of the integument are outlined in the 
micropylar region; X100; fig. 2, similar section about the time the cotyledons are 
first differentiated in the embryo; the upper portion of the endosperm has become 
cellular, while no cell walls have appeared in the lower portion; X33; fig. 3, later 
stage, showing further development of the embryo and of the cellular portion of the 
endosperm; X25; J, integuments; J, nucellus; E, endosperm. 
to the micropyle. This outer layer becomes differentiated some 
time before fertilization, and consists of closely packed, regular 
cells, characterized by the possession of rather dense granular 
contents and the absence of a vacuole. 
ae as Sok a ee Sant) | 
