152 ANDERSON: EMBRYOGENY OF MARTYNIA LOUISIANA 
and the second longitudinal, the one in the micropylar end divid- 
ing before the one in the chalazal end; but, in FIG. 32, it appears 
as if the first division had been longitudinal and the second 
transverse. The cytoplasm in the large cells around the fertilized 
egg contains many large as well as small vacuoles, while 
that of the lower cells contains only small ones. Very few 
plastids are present at this stage. They are seldom noticeable 
in later stages of endosperm development. Fic. 32 shows also 
the old densely staining pollen tube in the micropyle and upper 
end, of the embryo-sac, its tip covering the fertilized egg. By 
focusing down on the tip of the tube, the 
nucleus of the fertilized egg is seen and is 
represented in the drawing by a dotted line 
(Fic. 32). In the meantime, the whole em- 
bryo-sac has been enlarging at the expense 
of the integument which also has grown. 
The enlargement is more pronounced at first 
in the micropylar end where the fertilized 
egg is elongating. The layer of cells of the 
integument adjacent to the embryo-sac is 
always dense and rich in cytoplasm and func- 
tions as a nutritive jacket to the growing ~ 
endosperm. Fic. 33 shows the further de- 
velopment of the endosperm, and the 
elongation of the fertilized egg. The old 
pollen tube is still very prominent in the 
G56.” Outils micropyle and upper end of the sac, obscur- 
of Pie x 44. I, integ- ing the upper portion of the fertilized egg-cell. 
ument; M,embryo-sac The cytoplasm in the large endosperm cells 
E, embryo; U, suspen- of the micropylar end is very vacuolate, due 
sor; T, old pollen tube. 
probably to the rapid growth of the cells and 
to the loss of food to the developing embryo. Only a few 
endosperm cells develop in this end of the sac, for very soon 
a long suspensor is formed which brings the embryo into the 
chalazal end. The endosperm cells in the middle of the sac 
are smaller and richer in cytoplasm than the upper ones. The 
antipodals have nearly reached their maximum growth. They 
seem to function as elaborators of food and persist long after 
the embryo-sac is well filled with endosperm (FIG. 35). In 
several cases, four antipodals, all well developed, were found 
(Fic. 33). The extra one had probably been formed by the 
