196 



Kansas State Board of Agriculture. 



wild leaf -cutter bee (Megachile). The wind, threshing the branches 

 about, causes the springing or tripping of many flowers. Many are also 

 tripped automatically on sunny, dry days. On such days one can often, 

 sitting in the midst of an alfalfa field in full bloom, hear distinctly the 

 succession of tiny "clicks" caused by the tripping flowers. 



FIG. 169. Alfalfa flower (magni- 

 fied) after tripping, showing the col- 

 umn of stamens and. pistil, c, which 

 have escaped from the keel and have 

 struck against the standard. 



FIG. 170. Highly magnified view 

 of the column of stamens and pistil 

 after tripping. Column of stamens, c; 

 single stamen, 8; anther or pollen sack, 

 a; pollen escaping, p; standard petal, 

 st. The tip of the pistil is surrounded 

 by the anthers and is not visible. 



In order to trip many flowers of a plant rapidly, and secure many 

 seeds, it is necessary to adopt a more rapid method than that of tripping 

 each individual flower singly. This is accomplished by taking a head, or 

 raceme, of flowers between the thumb and forefinger, and gently twisting 

 the thumb and finger about the flowers, pinching them, and thus spring- 

 ing the mature flowers in rapid succession.* If extensive field work is 

 being done, the more rapid method, suggested by Westgate,f of grasping 

 the entire plant at the base with the hands, working the hands up the 

 plant and squeezing the plant at intervals, is to be preferred. These suc- 

 cessive compressions result in tripping a majority of the flowers. By 

 repeating the process a day or two later most of the remaining flowers 

 will also be tripped. By this means a considerable quantity of self- 

 fertilized seeds can be obtained, and a desirable type of plant can be ex- 

 tensively increased. By first increasing a single plant by means of cut- 

 tings, several hundred individuals identical with the original may easily 

 be obtained, and by the rapid method of self-pollination the progeny may 

 then be vastly increased in a very short time. 



* "Alfalfa Breeding, Materials and Methods," by Roberts and Freeman, Bull. 151, 

 Kansas Exp. Sta. 



t "Methods of Breeding Alfalfa by Selection," by V. M. Westgate, Am. Breeders Ass'n 

 Kept., vol. 5, p. 144 (1909). 



