Xll 



CONTENTS 



Length of seed viability, 164 ; Conditions affecting the 

 duration of seed viability, 165; Moisture, 166; Age of 

 seed as affecting the resulting crop, 167; Effect of drying 

 on vitality of seeds, 168 ; Stratification of seeds, 169. 



CHAPTER VII 



THE DECLINE OF GROWTH AND THE REST-PERIOD 



Cessation of growth, 170; Occurrence of the rest- 

 period, 171; Greenhouse plants, 172; Maturity. 173; 

 Hardiness, 174 ; Acclimatizing, 175 ; Plant processes, 

 176; Cuttings, 177 ; The " turn of the year," 178 ; The 

 round of plant life, 179. 



104-108 



CHAPTER VIII 



THE PLANT AS AFFECTED BY UNFAVORABLE TEMPERATURE 

 Factors of environment, 180. The plant as affected 

 by excessive heat : Relation of heat to transpiration, 181 ; 

 Effect of heat on evergreens, 182; High temperatures, 

 183 ; Sprinkling in sunshine, 184 ; Sun-scald, 185 ; Tip- 

 burn of potatoes, 186. The plant as affected by exces- 

 sive cold: Effect of cold, 187; Relation of water to 

 freezing, 188 ; The power of plants to endure cold, 189 ; 

 Treatment of frost-injured plant tissues, 190 ; Destruc- 

 tion of terminal buds by cold, 191 ; The darkening of 

 the wood, 192; Splitting of wood, 193; Bark-bursting, 

 194; Root-killing of trees, 195; Killing of flower-buds, 

 196 ; KHling of flowers, 197 ; Destruction by ice, 198 ; 

 Heaving, 199. Methods of averting injury by cold dur- 

 ing the dormant period : Dry soil, 200 ; Pinching the 

 terminal buds, 201 ; Protection with non-conducting 

 materials, 202 ; Exposure, 203. Methods of averting 

 injury from cold in the growing period : The freezing 

 point, 204; The cause of hoarfrost, 205; Foretelling 

 frost, 206 ; The sling psychrometer. 207 ; Computing 

 the dew point, 208; Use of weather maps in pre- 

 dicting frost, 209 ; Cold-air drainage, 210 ; Factors tend- 

 ing to avert frost, 211 ; Influence of a body of water, 



109-128 



