PLATE 20 



A. — Blueberry plants, Vacciniuin corymbosum, made dormant without cold. These 

 blueberry seedlings, in 2-inch pots, were kept during the fall and winter in a greenhouse 

 at a temperature of 55 to 70 F. Although this is a very favorable temperature for 

 the growth of the blueberry, these plants shed their leaves and became completely 

 dormant, just as they ordinarily do when exposed to the frost and cold of an outdoor 

 fall and winter. The photograph was taken on January 25. 



B. — Chilled and unchilled blueberry plants. The six blueberry plants at the left, 

 after an outdoor winter chilling, were brought indoors on March 25, into a greenhouse 

 having a temperature of 55 to 70 F., and were repotted. On April 20, when the 

 photograph was taken, they had developed both leaves and flowers, while the six 

 plants at the right, which had been in the same greenhouse at the same temperature 

 all the fall and winter and were repotted on the same date as the others, were still 

 completely dormant. 



