1904] BILLINGS—TILLA NDSIA USNEOIDES 105 
was taken as an extraordinary development of antipodals, but cases 
were found where the three degenerate cells were lying beneath the 
tissue in the small pocket at the end of the embryo sac. The free 
endosperm nuclei gradually gather in increasing numbers against 
the endosperm tissue, finally forming walls about themselves but 
remaining readily distinguishable from the other tissue (fig. 24). 
The functions of the two tissues appear to be somewhat different. 
The originally formed cell-compact retains its richness of protoplasmic 
contents during the development of the embryo, probably serving 
in the conduction of food materials to the later formed tissue adjoining 
it, which soon shows signs of containing food deposits. The reserve 
materials thus laid down are not utilized by the embryo before seed 
germination, but exist as the endosperm of the ripe seed. The endo- 
sperm at the micropylar end of the embryo sac does not develop in 
large quantity, forming a tissue about the embryo only after the 
latter attains a considerable size. _ 
The egg cell remains dormant for a time after fertilization. In 
1903 the period of blossoming lasted (at Baton Rouge) for a month 
following the middle of May. Material gathered about the first 
of July showed egg cells undivided, as well as embryos of only a few 
cells. Growth during the summer is slow, small embryos being 
found in material gathered about the tenth of August. It was not 
till the middle of September that large ones were observed, and even 
then there was much diversity in size. 
The first wall formed in the division of the egg cell is transverse, 
as is the second one also. The proembryo of three superimposed 
cells is therefore not different from the type that holds in so many 
monocotyledons. The divisions immediately following, however, 
vary considerably in sequence. 
The middle segment may divide sooner than the terminal (fig. 
28), or the reverse may be true (fig. 27). The basal segment divides 
sooner or later by longitudinal walls into four cells—a variation from 
the Alisma-type, in which the segment is unicellular and vesicular. 
The terminal segment divides by longitudinal walls to form the 
quadrant, and by transverse walls to form the octant. The latter 
walls instead of being precisely transverse may be oblique (jig. 34). 
In many older embryos the arrangement of the cells in this segment 
