2 Muhlenbergia, Volume g 
meagre that it was almost impossible to identify the species, and 
the addition of three new species to the group. The work is 
being carried on as a project under the Adams fund of the Ne- 
vada Agricultural Experiment Station. 
COROLLAS 
The vexillum or standard in this group has the free tenth 
stamen attached to or with it at the base, the filament joining 
with the main central vein. It is never attached for more than 
2 millimeters. The lower lateral margins of the vexillum are 
curved inward to a greater or less extent, varying with the spe- 
cies. At the lower central portion a depression from within 
outward takes place, forming a sort of pouch. This is variable 
in the different species, increasing with the age of the flower. 
It is probably caused hy the ene up of the ovary to form 
the legume. 
The filaments of the remaining nine stamens are joined to- 
gether for about three-fourths of their length to form a tube 
open down one side. The claws of the wings and keel are so 
closely associated with this stamen tube on its outer surface that 
it is difficult to determine whether they are actually joined with 
the tnbe or not. In both boiled dried specimens and fresh flow- 
ers, the claws have to be forcibly removed from the back of the 
stamen tube. The free portion of the filaments are conspicu- 
ously dilated near their junction with the anthers. The style 
also 1s dilated towards its upper half. These observations refer 
only to this group of the genus. 
POLLINATION 
Although there is an abundance of literature on the pollina- 
tion of clovers, particularly the European species commonly 
used as forage crops, very little can be found treating of the na- 
tive American species. 
We have been able to produce seed abundantly from this 
group of clovers without the aid of iusects. In the laboratory 
in the dead of winter, without even a fly about, the different spe- 
cies set seed freely. This experiment was repeated numerous 
times in the greenhouse with the same result. We are inclined 
