320 CHROMOSOMES IN HEREDITY : PHYSIOLOGICAL 



the last first, the stringency of ehmination increases in the following 

 series : Animal egg, animal sperm, embryo-sac, pollen, plant or 

 animal zygote. Taking the size of the fraction : the higher the 

 proportion of the haploid complement reproduced in excess (up to 

 one-half) the greater the reduction of viability. Taking the 

 disproportion of the excessive fraction : the higher the disproportion 

 the more aggravated is the defect produced. 



Table 49 

 Transmission of Extra Chromosomes of Triploids to their Progeny * 



3x X 2x {i.e.. through eggs). 

 CEnothera Lamarckiana. 



x^j. vanOvereem, 1921 

 (E. biennis, x = 'j. van 



Overeem, 1920 

 Datura Stramonium. ;tr= 12. 



Belling & Blakeslee, 1922 

 Solanum Ly coper sicum. 



X = 12. Lesley, 1928 . 

 Zea Mays, x = 10. 



McClintock, 1929 



2x X 3.r {i.e., through pollen). 



CEnothera Lamarckiana. 



X = -J . 

 Petunia, x = ']. Dermen, 



1931 .... 

 Solanum Ly coper sicum. 



;v = 12. 

 Zea Mays. ;r = 10 . 



41 



215 



10 



IX+X 



9 



26 



381 



38 + 



2;t + 2 



lOI 



16 + 



2.r-f3 2:t + 4 



2;t+5 2X + 6 2X+y 



Zx selfed. Crepis capillaris (;ir = 3) x C. tectorum {x = ^). Hollingshead, 

 1930 h. CCT plant (from unreduced egg. 2X = CC = 6 ; ^x = CCT 

 = 10 ; 4x = CCTT = 14. 



* Cf. Nishiyama, 1934, ^^d Levan, 1935, for further data. 



* All of the composition CCT {^x). 



t Composition CCTT, i.e., true 4X {cf. Table 26). 



Random expectation should be multiplied by 101/256. 



