96 BOTANICAL GAZETTE [AUGUST 
definite cell wall (figs. 23, 25, 26). Each grain of the pollen 
tetrad has a bare, circular, germinating pore for the exit of the 
pollen tube (fig. 24). Although it is generally stated that the 
tetrads in Zypha latifoa do not separate until after shedding, I 
often found them in large numbers entirely separated for some 
time before the anther was ready to dehisce (jigs. 25, 26). This 
cannot be given, therefore, as a character to separate it from 7. 
angustifolia, as is frequently done. 
DEVELOPMENT OF THE CARPEL. 
The carpels originate in a manner quite similar to the 
stamens, appearing first as small irregular papilla-like protuber- 
ances on the axis (figs. 27,28). As the young branch, which is 
destined to become the carpel, increases in size, irregular out- 
growths appear on its sides, which represent the beginnings of 
the carpellary hairs. These are entirely epidermal in origin, 
and are produced in acropetal succession, being irregularly 
arranged on the axis (figs. 29, 32,44). It is not at all probable 
that such irregular epidermal appendages represent reduced 
perianth structures, and I am inclined to regard these hairs as 
having merely a physiological significance, developed for the 
protection and dissemination of the seed. After the carpellary 
branch has attained some size, there arises on its summit an 
annular zone, leaving a deep depression, on the inner face of 
which the nucellus is developed, while the part of the ring 
opposite the nucellus develops into the spatulate stigma (jigs. 
32, 34). 
The nucellus is lateral in position and soon becomes pendu- 
lous because of its downward growth and the increase in depth 
of the cavity below (figs. 33-38). The ring above the nucellus 
is soon constricted, leaving little if any opening to the exterior 
(jigs. 33, 37). After the integuments begin to appear the ovule 
gradually takes on its anatropous condition until the nucellus is 
turned outward and points in exactly the opposite direction from 
its original position (figs. 38-48). The integuments are two in 
number, although the outer one is not developed on the side 
