CONTENTS ix 



PAGE 



113. Soil Temperatures 92 



114. Plant Temperatures 92 



Experiment 31 . Temperatures of Plant and Habitat 93 



115. Variations of Temperature 94 



116. The Influence of Other Factors 95 



117. Favorable and Unfavorable Temperatures 95 



118. Freezing 96 



Experiment 32. Effects of Freezing 97 



119. The Sum of Temperatures 97 



120. Influence upon Vegetation 98 



121. Digestion 99 



122. Chemosynthesis of Digested Materials 100 



123. Respiration 101 



124. Fermentation 102 



125. Germination 102 



Experiment 33. Digestion and Respiration in Seeds 103 



126. Nutrition of Hysterophytes 104 



127. Kinds of Parasites 104 



Experiment 34. Nutrition of Representative Hysterophytes 105 



128. Growth 106 



129. Growth of Tissues and Organs 106 



Experiment 35. Regions of Growth 107 



130. Conditions that Influence Growth 108 



131. The Amoimt and Rate of Growth 108 



132. Regions of Greatest Growth in Various Organs 109 



Experiment 36. Influence of Temperature, Water and Light upon 



Regions of Growth 110 



133. Rhythm of Growth 110 



134. The Age of a Plant 112 



135. Reproduction 112 



136. Propagation 113 



137. Propagules of Flowering Plants 114 



138. Stems as Propagules 114 



Experiment 37. Propagules 115 



139. Sexual Reproduction 115 



140. Production of Pollen 116 



Experiment 38. Amount of Pollen 118 



141. Protection of Pollen 118 



142. Structural Protection 119 



143. Protection by Movement 1-0 



144. Seasonal Protection l-'l 



Experiment 39. Protection of Pollen 122 



145. Disposition of the Stamens and Pistils 122 



Experiment 40. Grouping of Stamens and Pistils 123 



146. Source and Destination of Pollen 124 



147. Cross-pollination ' -> 



148. Pollination by Insects 1-6 



