1922] COFFMAN—POLLINATION IN ALFALFA 199 
tions were made by removing first the standard, and then one of 
the wing petals, thus exposing the interior of the flower to view. 
Care was taken not to set off the tripping mechanism, nor to disturb 
Fic. 3.—Young alfalfa flower called “hooded bud” stage; standard petal has 
risen Sealy to full height, and is beginning to spread; wing petals distinctly seen 
protruding, folded over keel, which is not yet visible. 
—Alfalfa flower fully open and ready for tripping, representing ‘erect 
dae > aes standard fully risen and spread; wing petals are separating, showing 
keel within. 
the stamens or otherwise injure the flowers. Flowers believed to 
have been injured in the dissecting process were discarded and not 
recorded 
