PLATE 30 



A. — Trailing arbutus, Epigaea repens, flowering sparingly from lack of chilling. 

 This plant of trailing arbutus was grown from seed. In the autumn, when about 

 a year old, it laid down clusters of flowering buds. It was kept in a warm green- 

 house all winter, but when flowering time came most of its flower buds were dead 

 and brown. Only a single flower opened. 



B. — Trailing arbutus plant flowering normally after chilling. This plant had the 

 same history as the plant described under A, except that it was kept outdoors during 

 the winter and brought back into the greenhouse in the spring. At the age of 14 

 months, when the photograph was taken, March 27, 1011, the plant was in full flower, 

 healthy and normal. 



C — Blueberry plant forced into flower in September by artificial chilling. This 

 plant was brought indoors in late winter. It made new growth, and during the cool 

 weather of May it laid down flowering buds for the next year, as a blueberry plant 

 ordinarily does in autumn. During the summer, however, the plant was given an 

 artificial winter by chilling it for three months in an artificially refrigerated glass- 

 covered frame exposed to daylight. When brought out of the frame, in September, 

 the plant promptly flowered, as shown in the illustration. 



