xvi AGRONOMY 



PAGE 



CHAPTER XVIII. PLANT BREEDING 258 



Need for breeding. Basis for breeding. Inducing variation. Hybrids 

 and hybridizing. Producing the cross. Mendel's law. Selection. 

 Roguing. Xenia. Parthenogenesis. Practical exercises. 



CHAPTER XIX. THE ORIGIN OF SPECIES 272 



Evolution. Struggle for existence. Natural selection. Results of 

 variation. Darwinian theory. Mutation theory. Practical exercises. 



CHAPTER XX. OUR CULTIVATED PLANTS 277 



Origin. Edible parts of plants. Root crops. Leaf crops. The 

 legumes. Solanaceous fruits. Gourd fruits. The grasses. Bush 

 fruits. Tree fruits New fruits. Practical exercises. 



APPENDIX 



SEVENTY-FIVE SHRUBS USEFUL FOR PLANTING 285 



FIFTEEN WOODY VINES DESIRABLE FOR ARBORS AND PORCHES . 288 

 FIFTY DESIRABLE HERBACEOUS PERENNIALS 289 



INDEX . . 291 



