
102 BOTANICAL GAZETTE [AUGUST 
inner walls of the ovary, and by the time of the formation of the 
mature sac some of them reach almost halfway to the level of the 
apex of the placenta (text figs. 20, 21, fe). By the completion of the 
development of the embryo sac, there are 10-12 vascular traces 
distributed between the three main bundles of the perianth, with 
which they have become united (text fig. 21,2). Besides uniting with 
the bundles of the perianth, 
~. 

é ‘ 
, Sey es 
te. e+ 
Fie. 44.-<Di 

fig. 20 and A, B,C, and A, B, Cin fig. 8; 
t, tp, tc, 8, ca, m, 0, as in fig. 20; es, embryo 
sacs. 
of the style. 
their branches anastomose 
with each other, so that in 
the mature fruit there is an 
intricate network of vessels 
within the fleshy pericarp. 
The vessels, formed in the inner 
wall of the carpels, constitute 
their vascular system. The 
embryo sacs are in close prox- 
imity to some of these vessels, 
while ‘later the endosperm 
comes to be in direct contact 
with them. In the ripe fruit 
the outer coat of the lower 
half of the seed is formed of 
remnants of these tracheids. 
Two small strands of. tra- 
cheids pass upward from the 
vascular complex in the lower 
part of the carpels to the base 
These strands lie in the plane of flattening of the 
floral AXIS (text figs. 20, 21, tc). The tissue between these strands 
is eventually displaced by the endosperm, which then lies in contact 
m. 
with the 
Development of the megaspore 
Previous to the upward growth of the torus, as explained above, 
the arch 
“mamelon,” 
€sporial cells become organized. 
There are two in each 
hypodermal in origin and located at the poles of the 
mid-horizontal diameter of the enlarged floral axis (fig. 23). They 
