293 
grown is held firmly, while the growth near the apex forces the 
tip further and further into the soil. 
In conclusion, it remains to be considered how much the facts 
ascertained in this study contribute to the solution of the question 
undertaken. 
The fact that so many of the Leguminosae seek the ground 
in order to develop their fruit and that such different methods are 
employed in the accomplishment of this result must be re- 
garded as having some important significance. 
Tschirsch in an article on the root tubers of the Leguminosae, 
in the Berichte der Deutschen Bot. Ges. 1887, states that one 
group of nitrogenous compounds produced by the Leguminosae 
can be formed only in darkness and suggests this as a reason for 
the subterranean fruit of so many species of this order. This ex- 
planation does not answer the question satisfactorily, as Trifolium 
Subterraneum plainly seeks to place its fruit under ground, and yet 
may both ripen and germinate it above ground. Beyond this the 
statement that some nitrates can only be formed in darkness does 
not meet with the concurrence of all authorities. It has also been 
suggested that the subterranean development of fruit is to enable 
it to avoid the danger of being eaten by grazing animals. These 
are the only reasons which have been offered in explanation of 
this phenomenon. 
In reviewing the results obtained in this study, three facts 
stand prominently forth: namely, the absence of hairs on the 
root, the presence of hairs on the gynophore which may perform 
the chief function of root hairs, and lastly, the increased size of 
the subterranean part of the gynophore caused by a growth simi- 
lar to that producing periderm. 
While these facts alone are by no means sufficient to account 
for the underground development of the fruit they may at least 
furnish some evidence as to what is accomplished by this process. 
That the plant is able to take up water from the soil by means of 
the gynophore hairs was shown in the experiment where the roots 
were severed from the stem. The most puzzling feature in the 
anatomy of the gynophore is that of periderm formation in the 
Portion under ground. In the large number of gynophores ex- 
amined this was a constant feature of the subterranean portion, 
