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minate as soon as they begun to bave the plant; and the percentage 

 of germination increased directly in proportion to the degree of 

 maturity. Flower heads cut off with a lawn mower immediately 

 after blossoming failed to produce seeds capable of germination. 

 Therefore it seems safe to conclude that a lawn clipped regularly 

 and at least once a week will not be a source of contamination for 

 clean lawns in the neighborhood. However, some seed heads which 

 lie close to the ground escape the mower blades. These must be 

 removed by hand picking or with a dandelion rake if seed formation 

 is to be entirely prevented. 



In the germination tests of the seeds used in the study of partheno- 

 genesis it was found that a quicker response was secured when the 

 range of temperature was greater than that ordinarily used, i.e., 

 when the temperature was permitted to rise to 38 C. for a very short 

 time. Also, it was found advisable to place a small piece of folded 

 blotting paper along with the seeds between the folds of paper to 

 facilitate aeration. 



DANDELION ERADICATION EXPERIMENTS. 

 ERADICATION EXPERIMENTS AT THIS STATION PRIOR TO 1912. 



The results of lawn spraying experiments conducted by French 

 (1911), while showing the iron sulfate treatment to be partially 

 successful, did not seem to warrant its recommendation as a practi- 

 cable method of control. A strip of lawn was sprayed six times 

 during each of two successive seasons, using, the first season, 1.5 

 pounds, and the second season, 2 pounds of iron sulfate in each 

 gallon of water. While this treatment prevented blooming of the 

 dandelions, and even killed many of the plants, a considerable 

 number remained alive when the experiments were necessarily 

 discontinued at the middle of the second season because of severe 

 injury to the grass. Apparently, the stronger solution used the 

 second season caused considerable injury to the grass as mid-summer 

 approached and the rate of growth of the grass decreased owing to 

 unfavorable weather conditions. In summarizing the results of his 

 experiments with iron sulfate solution, French stated that it was 

 not clear why dandelion spraying should fail in New York when 

 it had been successful elsewhere. He further stated that " the failure 

 of the treatment seemed to be due to the great vitality of the dande- 



