Polygala polygama and P. paucifiora. 131 
ness of the wall at first, and the subsequent great increase in 
size are clearly shown. When ripe, the microspore has 
increased to several times its bulk and is nearly spherical. It 
will be seen that the thickened meridional ridges are at first 
sunken in inrolled grooves, that later they are pressed out to 
the level of the spore wall and finally come slightly to project. 
Iam not aware that this increase in size has been noted in 
other plants. An examination of series of pollens from 
fhibiscus, Rondeletia, Clerodendron, etc., showed that the 
microspores are nearly constant in size after the budis well 
formed. 
Andrecium.—B. The Aérial Cleistogamic Flower. In this 
the eight stamens typical of the chasmogamic flowers are 
nearly always represented, part of them in a rudimentary con- 
dition. The largest of these cleistogamic anthers, however, 
are smaller than those of the chasmogamic, and contain a less 
number of microspores (60-120). The superficial cells show 
quite clearly the stellate thickenings which aid in dehiscence. 
The microspores are also smaller, in the ratio of about six to 
seven. A similar increase in size takes place in them, but the 
range is not quite so great, and the wall always remains thick. 
Andrecium.—C. The Subterranean Cleistogamic Flower. 
In this the stamens are greatly reduced both in size and num- 
ber. Sometimes only two bear perfect microspores. Rudi- 
mentary anthers are always found. The number of stamens 
as well as their development varies, but more than seven seem 
never to be represented. A well-developed anther may con- 
tain 40-80 microspores. The superficial cell-walls of the 
anther show only a faint indication of the stellate thickenings 
so prominent on the surface of the same in the chasmogamic 
flowers. The microspores are still smaller than in the pre- 
ceding type, as may be seen in Figure 9, and the wall is 
relatively very thick. This thickness of the microspore wall 
in the minute flowers seems quite remarkable, and is the 
