Smithsonian Report, 1919.—Coville. PLATE 12. 
DORMANT BLUEBERRY BUDS STIMULATED TO GROWTH BY CHALKING THE STEM. 
This plant was brought into the greenhouse February 4, 1913, to be used in breeding experiments. It 
flowered, but having been insufficiently chilled, only a few of the uppermost leaf buds on each stem 
grew. In order to keep small ants from crawling up the stems and interfering with the pollination 
experiments, the stems were chalked near the middle. The dormant buds in and just below the 
chalked area started growing. The photograph was taken April 5, the stems being rechalked over 
the same areas that were originally chalked. After numerous repetitions of the experiment it was 
found thatif the chalking was donelightly the buds would not grow, butif the stems were rubbed hard 
in the process of chalking, as commonly happened in the case of very smooth stems, the buds grew. It 
was the hard rubbing, not the chalk, that stimulated the growth. (Naturalsize.) 
