iv Contents. 



PAGE 



15. Hesperis Matronalis 136 



16. Clarkia Pulchella 144 



17. Plantago Lanceolata Ramosa 148 



VI. Experimental Observation of the Origin of Varieties. . 161 



18. The Origin of Chrysanthemum Segetum Plenum .... 161 



19. Double Flowers and Flowerheads 194 



20. The Origin of Linaria Vulgaris Peloria 201 



21. Heritable Pelorias 220 



VII. NON-ISOLABLE RaCES .♦ 22/ 



22. Trifolium Incarnatum Quadrifolium 227 



23. Ranunculus Bulbosus Semi-Plenus 243 



24. Variegated Leaves 265 



25. Alternating Annual and Biennial Habit 291 



VIII. Nutrition and Selection of Semi-Latent Characters. 307 



26. Increased Nutrition Favors the Development of the 



Anomaly 307 



27. The Influence of External Conditions and of Manur- 



ing 315 



28. The Periodicity of Semi-Latent Characters s^3 



2g. The Choice of Seeds in Selection 332 



PART II. 

 THE ORIGIN OF EVERSPORTING VARIETIES. 



I. Tricotylous Races 343 



1. The Occurrence of Tricotyls as Half Races and Inter- 



mediate Races 343 



2. Tricotyls, Hemi-Tricotyls and Tetracotyls 356 



3. The Influence of Tricotyly on the Arrangement of 



Leaves 365 



4. Tricotylous Half Races 379 



5. Tricotylous Intermediate Races Do Not Arise by Se- 



lection 393 



6. The Isolation of Tricotylous Intermediate Races .... 417 



7. Partial Variability of Tricotyly 444 



8. The Influence of External Conditions on Tricotyly . . 450 



II. Syncotylous Races 457 



9. Hemi-Syncotyly, Syncotyly, Amphi-Syncotyly 457 



10. Helianthus Annuus Syncotyleus 466 



11. Improvement of a Hemi-Syncotylous Race 476 



12. Atavistic Races ■■ 481 



