122 White. 



to 1 normal. The three classes were clearly recognizable and very 

 distinct, the heterozygote always being an intermediate. No segregation 

 of other factors, which might have been hypostatic (as in Bateson's 

 sweet peas) occurred. The total progeny of 304 X 402 Aa plants gave 

 an extremely close approximation to the theoretical expectancy. 

 Actual ... 98 AA:192 Aa : 103 aa; Total 393, 

 Theoretical . . 98 AA : 197 Aa : 98 aa; „ 393. 



12. Four generations of the cross (304 X 402) have been grown 

 and the Fo segregates have all bred true to their respective character, 

 AA plants producing . always AA, Aa individuals always producing the 

 original F2 ratio of 1:2:1, and aa plants always giving rise to aa 

 progeny. F2 normal segregates and their Fs and Fi progeny have 

 possessed two or three abnormal flowers. These, as pointed out in the 

 body of the paper, may be interpreted by some biologists as evidence 

 in favor of a theory of gametic contamination as opposed to that of 

 gametic purity, because I have nothing better than casual observations 

 to prove that the normal 402 plants have the same character in the 

 same degree. This character is not hereditary in the strict sense, and 

 upon the fixed unit factor conception, these slightly abnormal flowers 

 may be explained as accidents in ontogeny. 



13. The cytological investigations of the maturation phenomena 

 in the anthers and ovaries of the pure abnormal (300 — 309) race showed 

 numerous irregularities in the normal processes of reduction. Chromatin 

 and cytoplasm were alike affected, and many of the pollen mother- 

 cells were destroyed through the presence of factor A. Only a certain 

 percentage of anthers and ovules are abortive, and this partial sterility 

 is made good as far as seed production is concerned by the increase 

 in the number of ovules and ovary -locules. In crosses with 402, the 

 Fl plants show the same irregularities, but to a lesser degree and in 

 a lesser number of anthers. The cytological observations on the F2 

 generation show that a perfect correlation exists between the gross 

 morphological and cytological features of this fasciated race. The factor 

 for fasciation then produces its abnormal effect even in the germ-cells, 

 and this effect is subject to alteration in both somatic and germinal 

 structures through changes in dominance. The same factor A expresses 

 itself in the soma by altering ,the form of many of the characteristic 

 organs, and in the germ -cells by destroying a certain percentage of 

 cell materials, or by producing irregularities in their normal processes 

 which ultimatelv cause their own destruction. Because of the F2 ratio 



