CONTENTS. XI 



Leaves. Acacia of Arabia. Conversion of Petioles into Tendrils, 

 of young Shoots into Thorns. Difference of Thorns and Prickles. 

 Diseases of Plants ranged under Six Heads: 1st Class, Constitutional 

 Diseases. Variegated Leaves. 2d Class, Diseases produced by 

 Light, Heat, Water, Air, or Soil, improperly applied. 3d Class, 

 Diseases from Contusions and external Injury. Loss of Leaves and 

 of Bark. Flagellations. Unskilful Pruning. Pollarding. 289 



CONVERSATION XXVII. 



THE DISEASES OF PLANTS CONTINUED. 



4th Class, Diseases arising from the Action of Animals on Plants. De- 

 vouring of Leaves by Quadrupeds or Insects, &c. 5th Class, Action 

 of Plants on each other. Parasitical Plants. True and False Par- 

 asites, External and Internal. Creeping Plants. Rhizomorpha. 

 Mistletoe. Cuscuta. Orobanche. Fungi. Erishe. Rhizotonia. 

 Smut. Rot. Ergot. Rust. 6th Class, Diseases resulting from 

 Age, and causing the Death of Plants. ... 301 



CONVERSATION XXVIII. 



ON THE CULTIVATION OF TREES. 



Greatest Variety of Trees in tropical Climates. Natural Forests, tol- 

 erant and intolerant. Thirty-four Species of European Forest 

 Trees, divided into Four Classes. Various Modes of Felling Forests. 

 Wood for Fuel. Cultivation of single Trees. Of Lopping Trees. 

 Transplanting. Sir Henry Stewart's Process. Hedges. Fruit 

 Trees. - ... 310 



CONVERSATION XXIX. 



ON THE CULTIVATION OF PLANTS WHICH PRODUCE FER- 

 MENTED LIQUORS. 



Fermentation. Of Sap. Of Fruits. Of Grain, producing Wine, Beer, 

 Cider, Perry. History and Culture of the Vine. - 326 



CONVERSATION XXX. 



ON THE CULTIVATION OF GRASSES, TUBEROUS ROOTS, 

 AND GRAIN. 



Meadows, perennial, renovated chiefly by the Spreading of the Roots, re- 

 quire a moist Climate. Sustain the Soil on Declivities. Artificial 

 Grasses, not forming permanent Meadows, but entering into a 



