136 Shaw—Structure of the Flowers in 
testa. The cells of the outer coat form then a thin zone out-. 
side the indurated one, and bear the hairs which give the seed’ 
its silvery appearance. It is noteworthy that, long after the 
indurated layer has become so heavy that it would seem quite 
impervious to food, the cells of the outer piliferous layer retain 
their protoplasmic contents and nuclei, and seem like living cells. 
Meanwhile the aril has formed as a paired proliferation from 
the primine close to the funiculus and forms spongy masses of 
highly vacuolated cells. In the mature seed they are seen as 
a couple of whitish lobes, rather less than half the length of 
the seed. The seed is black, 2 4-3 millimeters in length, and 
clothed with hair. 
In looking over the structural features it is seen that the 
aerial cleistogamic flowers show intermediate stages between 
the other two types alike in form, in position, in develop- 
ment of sepals, petals, stamens and carpels, and in the minuter 
details of these, the whole constituting perhaps as neat an 
illustration as is possible, of the stages whereby a plant 
reaches a highly modified development. 
Various experiments have been made by cutting off one or 
another type of inflorescence to ascertain how far growth 
correlation and compensation might be exhibited. Plants 
deprived in early July of their evident racemes, developed 
others from axillary buds. Removing the subterranean clus- 
ters had no visible effect on the plant and they were not 
replaced. Subterranean flowers that were exposed turned 
green within three days. 
The production of the aérial cleistogamic flowers appears to 
be dependent on the general vigor of the plant, for in one 
very dry season they were almost wholly lacking. 
POLYGALA PAUCIFOLIA. 
As mentioned above, the only other species of the genus 
Polygala which bears cleistogamic flowers is P. paucifolia, the 
