742 
DUNCAN S. JOHNSON 
EXPLANATION OF FIGURES 
15 Section of the stamen shown in the last figure, several sections removed from 
the one there shown. X 160. 
16 Transverse section of a nearly mature stamen with four microsporangia. 
X 75. 
17 Section of nearly ripe pollen-grain, showing mitosis of first division. 
X 1000. 
18 Section of older, two-celled pollen grain. X 1000. 
19 Ripe pollen-grain, in which the wall has disappeared. X 1000. 
20 Transverse section of half-mature stamen with four microsporangia. 
X 100. 
21 Transverse section of stamen with three pollen sacs, of a staminodium and of 
a braci. X lUO. 
22 Transverse section of stamen, showing two sporogenous areas in the upper 
iv^«.uius and one in the lower. X 100. 
23 Another section of the same stamen, showing the continuity of the sporo- 
genous mass in the upper loculus. X 100. 
24 Transverse section of stamen showing one sporogenous mass in each locu- 
lus. X 100. 
25 Surface view of spike, showing bracts, stigmas and variety in distribution 
of the sporogenous masses. X 38. 
26 Transverse section of stamen with two sporangia in the lower loculus and 
none in the upper. X 100. 
27 Transverse section of a stamen with one sporogenous mass in the upper locu- 
lus and none in the lower. X 100. 
28 Transverse section of stamen with one sporogenous mass in the lower locu- 
lus and none in the upper. X 100. 
29 Transverse section of stajnen with one continuous sporogenous area. X 100. 
30 Transverse section of the same anther at a level nearer the base, apparently 
showing two sporogenous masses. X 100. 
31 Transverse section of anther showing continuous sporogenous mass across 
the anterior face of anther, while one sporangium in each loculus remains distinct. 
X 75. 
32 Longitudinal section of staminodium, of about same age as the stamens 
shown in figs. 20-30. X 160. 
33 Longitudinal section of flower and two bracts, showing relation of these 
structures and the complete submergence of the ovary in the axis. X 40. 
