STOUT: POLLINATIONS IN CICHORIUM INTYBUS 



383 



Darwin's contention regarding fertility in general, or whether 

 inbreeding and self-fertilization of pure races or strains gives the 

 greater fertility as Burck argues. Neither Darwin nor Burck 

 considered in this connection the sort of sterility (from physio- 

 logical incompatibility) seen in chicory. 



Self- sterility in hybrids betzueen a wild white-flowered plant and a 

 plant of the ''improved striped-leaf variety. — Further data on the 

 point just mentioned were gained from Fi plants obtained by cross- 

 ing a white-flowered plant {A X C) no. i with a plant of the variety 

 known as the "improved striped-leaf." The five plants of this 

 variety which were tested were fully self-sterile. The parent used 

 In this cross was one of the plants tested. The cross was originally 



TABLE 8 



Data for self-pollinations of Fi plants grown from a cross between {A X C) 

 NO. I and a plant of the variety "improved striped-leaf" 



Record for heads pollinated 



Dates 



Total 

 no. 



heads 



Remarks 



No. I . 



" 3- 



" 6. 



" 7- 



" 8. 



" 9- 



" II. 



" 12. 



" 14- 



" 15- 



" 16. 



" 17- 



" 18. 



" 19- 



" 20. 



" 21. 



" 23. 



" 24. 



" I. 



" 3- 



" 4- 



" 5- 



" 6. 



" 8. 



" 9- 



" 10. 



" II. 



" 12 . 



" 13- 



" U- 



II 



18 

 12 



8 



23 

 II 

 12 

 12 



17 

 12 

 11 

 10 

 II 

 II 



9 

 12 

 12 

 14 



16 



17 

 II 

 II 

 14 

 15 

 II 



5 



Series with {A X C) no. i as seed-parent. 



Series with {A X C) no. i as pollen-parent 



