486 WEATHERWAX: SPIKELETS OF ZEA Mays 
reduction division (PLATE 23, FIG. 4) show the typical parts as 
described by Golinski, and these, except the epidermis, are prac- 
tically all absorbed by the time the pollen is mature. For the 
greater part of the length of the anther its wall consists of merely 
the epidermis (Fic. 5), but for a short distance at the distal end 
this wall is reinforced by the mechanical layer (Fic. 6). As a 
Fics, 6-10. Development of the female spikelet, X 60. G, glume; L, lemma; 
F, flower primordium; S, stamen; P, palea; Pi, pistil; Si, silk; O, ovule; SC, stylar 
canal; W, wall of ovary 
result, it is only at the end of the anther that the loculi coalesce 
in pairs to form the two “‘cells,” and the opening is a pore formed 
by the turning back of the edges of a short slit extending along the 
anther as far as the mechanical tissue goes (Fic. 7). From this 
pore the pollen grains escape as the wind moves the anther about 
at the end of the long filament. 
The reduction division and maturation of the pollen do not 
furnish very satisfactory material for cytological work. The 
chromosomes are small and hard to differentiate clearly in the 
dense cytoplasm. Kuwada (4 and 5) has made a cytological study 
of a number of varieties and concludes that there is considerable 
variation in the size and number of the chromosomes. The 
haploid number in most varieties of sweet corn is found to be 
- twelve, and in other varieties the number is often smaller. To 
