* 
POLLINATION IN ALFALFA 
F. A. COFFMAN 
(WITH FIVE FIGURES) 
The problem of fertilization in alfalfa has been a matter of 
considerable controversy for several years. Many experiments 
have been performed in endeavoring to determine what factor is 
most largely responsible for pollination in this plant. In the review 
of investigations published by Piper, Evans, McKEEg, and Morse’ 
it is stated that the amount of self-pollination varies with the season, 
and that its real importance in seed production is doubtful. H1prE- 
BRAND? is cited as having believed as early as 1866 that fertilization 
may take place in untripped flowers, and URBAN? (1873) is referred 
to as thinking that in some cases untripped flowers form pods. 
Most of the work of recent investigators has consisted of attempts 
to determine the most important agents in tripping the alfalfa 
blossom. Although a considerable number of experiments have 
been carried on, no definite conclusions seem to have been reached. 
Roserts‘ found anthers dehiscing and stigmas pollinated in the 
early bud stages of the alfalfa. 
An investigation which was begun by the writer during the latter 
part of September 1916, and which was continued until killing frosts 
in October, had for its object the determination of the stage at 
which the stamens of the majority of alfalfa flowers really shed 
their pollen. It was found that light frosts do not seem to have 
any effect upon pollination, the percentage of pollinated to unpol- 
linated flowers not being affected so far as could be noticed in 
any of the classes of buds examined. 
Prrer, C. V., Evans, M. W., McKee, R., and Morsg, W. J., Alfalfa seed pro- 
duction; vitlication studies. Bull. 75. U.S. Dept. Agric. 1914. 
2 HitpeBranp, F., Uber die Vorrichtungen an einigen Bluthen zur Befruchtung 
durch Insektenhulfe. Bot. Zeit. 24:75. 1866. 
3 URBAN, I., Prodromus einer Monographie der Gattung Medicago. Verhandl. 
Bot. Ver. Provinz Brandenburg 15:13. 1873. 
4Roserts, H. F., Alfalfa varieties, breeding, seed, and inoculation. Quarterly 
Rept. Kans. State Board Agric. 35:180. 1916. 
197] [Botanical Gazette, vol. 74 
