126 Shaw—Structure of the Flowers in 
ing beneath the soil. In the axils of their small bracts are 
white or pinkish protuberances, the subterranean flowers. At 
the time of pollination they are about one millimeter in length, 
but after pollination they rapidly enlarge, and in a surpris- 
ingly brief period assume the proportions of seed capsules. 
Thus, although such flowers appear in the Wood’s Holl 
neighborhood from the fifteenth to the twentieth of June, about 
the same time with evident flowers, they ripen seed sooner. 
As early as July 4 seeds from these cleistogamic flowers may 
be found. Seeds are also produced much more abundantly 
from these than from the chasmogamic flowers. 
(3) AERIAL CLEISTOGAMIC OR INTERMEDIATE FLOWERS. 
Mention has already been made of the fact that another 
and unrecognized type of flower exists in this plant. In July, 
after both the evident and the underground cleistogamic 
flowers have been developing for a time, aérial branches may 
be seen bending downward. These bear, in addition to small 
leaves, little green tubercular bodies which are, in fact, another 
set of microscopic flowers. They are produced in such 
abundance, too, that small though they are, it is remarkable 
that they have never been clearly recognized and described. 
They are considerably larger than the underground type 
and bright green, while all parts of the flower are more devel- 
oped. Their development is generally associated with geo- 
tropic tendencies on the part of the shoot bearing them. It 
is especially striking to note that a leafy shoot, after having 
grown upwards and perhaps borne evident flowers, may begin 
to develop these small closed ones, and in so doing to bend 
over at its tipto pursue the opposite course. At Wood’s Holl 
experiments were tried of digging up sods of plants bearing 
geotropic shoots and inverting them. In a day or two the 
tips were seen to show reversed curvature, thus reasserting 
their geotropic tendencies, 
