CORRESPONDENCE 
157 
CORRESPONDENCE 
FOOD STORED BY THE BEAN MOUSE 
To the Editor of the Journal of Mammalogy: 
I read with great interest the article by Mr. Vernon Bailey in the February 
issue of the Journal on the Identity of the Bean Mouse. In regard to a state- 
ment in the third paragraph of that article perhaps it would be well to make here 
a slight correction. It was stated that ‘‘They are large, fleshy beans produced 
on underground shoots of a trifoliate bean vine, Falcata comosa.” 
Now as a matter of fact the large beans are not produced on underground 
shoots. They are produced underground on the extremities of branches which 
are above ground, running along the surface of the ground. These lower 
branches of the bean plant start out from the base of the main stem of the plant 
and run along the surface, making a perfect network of branches lying upon the 
surface of the ground under the overgrowth of the leafy branches of the plant 
which climb upon bushes and other vegetation. If the upper, leafy part of one 
of these bean plants be carefully cut away without disturbing the lower, basal 
branches they will appear like a lacy network of white threads upon the surface 
of the ground. 
Falcata grows in dense masses of vines over other vegetation in some places, 
using such vegetation to climb up into the air and light. It has two kinds of 
branches, the upper, climbing branches, and the basal, prostrate branches which 
creep along the ground in the shade of the upper growth. These two kinds of 
branches on the same plant produce two kinds of flowers, from which result two 
forms of fruits. The upper, leafy branches bear petaliferous, insect-attracting 
flowers, from which result small brown bean pods from one-fourth inch to one- 
half inch in length. Within these pods are produced 3, 4, or 5 small mottled 
beans of j-q to inch in length. 
The basal branches, in conformity with their position prostrate on the surface 
of the ground in the shade of the upper growth are leafless and colorless. Also in 
conformity with their position away from possible insect visitors their flowers are 
not petaliferous, but cleistogamous. This self-pollinated flower produces apod 
which at once pushes itself into the soft leafmold and loose soil and there develops 
its single large bean. This ground bean is about the size of the common lima 
bean, but not so flat. It is of uneven form but thicker, while not so long as the 
lima bean. 
The fruits of both upper and basal branches are equally useful to the species 
for reproduction, the one being supplementary to the other, and a sort of pre- 
cautionary provision in case of failure of production of either the one or the other 
from exigencies of weather or other conditions. Furthermore, it is a curious 
thing that if the fruits of the basal branches are unable to cover themselves in the 
soil they will develop in all manner like the fruits of the upper branches, grow- 
ing small and hard and covered with a thick pod instead of the thin membrana- 
ceous covering which develops when it succeeds in burying itself in the soil. Like- 
wise if the basal branches are exposed to the light they do not differ from the 
upper branches in color. 
Melvin R. Gilmore. 
Bismarck, North Dakota, 
March 9, 1920. 
