Volume IX JANUARY, 1920 No. 2 



FURTHER EXPERIMENTAL STUDIES ON SELF- 

 INCOMPATIBILITY IN HERMAPHRODITE 

 PLANTS. 



By A. B. STOUT. 



(With Plates III and IV.) 



CONTENTS. 



PAGE 



Statement of the problem and its relation to the old familiar sex questions 85 



Keview of the more recent literature 87 



Presentation of new data 93 



I. Eelation of vegetative vigour and maturity to variations in self- 

 fertility and self-sterility 93 



1. In Verbascum phoeniceum 94 



2. In Esehscholtzia califonnca 96 



8. In Nicotiana Forgetiana Hyb. Hort 100 



4. In Brassjca pekinensis ...... 103 



5. In Raphanus sativtis ....... 104 



6. In Lythrum Salicaria . . . . . . . 104 



7. In Li nuin grandijlorum. ...... 105 



8. In Cichorium Intybus 105 



II. Evidence that self-incompatibility may lead to certain cases of 



embryo abortion ......... 107 



III. The heredity of self-compatibility in self-fertilized lines of descent 



in the variety red-leaved Treviso of Cichorium Intybus . . 108 



1. The Jj generation 109 



2, The I2 generation 109 



IV. Vegetative vigour and impotence in self- fertilized lines in the 



variety red-leaved Treviso of Cichorium Intybus . . . 116 



1. A degenerate line of descent 117 



, 2. Families of marked vegetative vigour .... 118 



Discussion and Conclusion 120 



Experimental studies of the compatible and the incompatible 

 relations of the sex organs (including germ cells) in the fertilization of 

 hermaphrodites continue to yield evidence that these relations are 

 highly fluctuating in the progeny of a single cross- or self-fertilized 



Journ. of Gen. ix 6 



