XVUl CONTENTS. 



CHAPTER IV. 



Pack 



action of leaves. 



Their Nature, Structure, Veins, Epidermis, Stomates. — E£feet of 

 Light — Digestion or Decomposition of Carbonic Acid. — 

 Insensible Perspiration. — Formation of Secretions. — ^Fall of 

 the Lea£ — Formation of Buds by Leaves . . . .87 



CHAPTER V. 



ACTION OF FLOWEBS. 



Structure of Flowers. — Names of their Parts. — Tendency of the 

 Parts to alter and change into each other, and into Leaves. — 

 Double Flowei's. — Analogy of Flowers to Branches. — Cause 

 of the Production of Flowers. — Of Pi-oductivenesa — Of 

 Sterility. — Uses of the Parts of a Flower. — Fertilisation. — 

 Hybrids. — Crossbreds 66 



CHAPTER VL 



OF THE MATURATION OF THE FEUIT. 



Changes it undergoes. — Superior and inferior Fruit — Is fed by 

 Branches upon organisable Matter furnished by Leaves. — 

 Physiological Use of the Fruit. — Nature of Secretions. — ^The 

 Changes they undergo. — Effect of Heat — Of Sunlight — Of 

 Water. — Seeds. — Origin of their Food — Cause of their Lon- 

 gevity. — Of their Destruction. — Difference in their Vigour . 69 



CHAPTER VIL 



OF TEMPERATURE. 



Limits of Temperature endurable by Plants. — Effects of a too 

 high Temperature. — Of a too low Temperatui'e. — ^Frost. — 

 Alternations of Temperature. — Day and Night. — Winter and 

 Summer. — Temperature of Earth and Atmosphere . 79 



