CHARACTER AND RATE OF GROWTH IN STEMS 219 
plants as Corn, Beans, and Pumpkins grow slowly, White Mus- 
tard and other plants with a low optimum grow rapidly. In gen- 
eral, arctic plants have a lower optimum than tropical plants, and 
consequently plants transferred from one region to the other 
Fic. 199. — Pines grown much crowded and consequently producing slender 
trunks. From Bulletin 24, North Carolina Geological and Economic Survey. 
usually do not thrive until they become acclimated, that is, 
until the plant’s protoplasm becomes adjusted to the tempera- 
ture of the region. 
GROWTH TEMPERATURES IN FAHRENHEIT 
Plant. Minimum. Optimum. Maximum, 
Deg. Deg. Deg. 
Barleys = aiscinnveneunk woman eae s 41 83-84 99-100 
White Mustard.................... 32 69-70 82-83 
Scarlet Runner Bean.............. 49-50 92-93 115-116 
COE edict cesar ee EA ORE LES 49-50 92-93 115-116 
PUMPKIN eres cae eacseeneenearas ae 56-57 92-93 115-116 
