1030 



tiling óf' lliis kind was obscrvod by Cokrens ^) on crosyiiig' a black 

 sugar maize Zea yfnis vac. cnendcodnhis KcKe. and a common 

 white maize "Popcorn", Zea }f(iis var. /eiicoceras Alef. Here a 

 deficiency of sacchariferoiis granules occuri'ed. Correns showed by 

 crossing the i'Vliybrid again with the sugar-containing P-form, 

 that the formation of an unequal number of the different gametes 

 was not the cause of the phenomenon. He comes therefore to the 

 conclusion that the deficiency arises because the gametes-combination 

 of two sacchariferous ones happens less easil}'. 



By crossing the varieties of flax a further deficiency was caused 

 through the seed of the white forms having less germinating-power. 

 It either does not germinate at all, the embryo has tiien already 

 died in the seed, or the seedlings die off early. The latter agrees 

 with the case observed by Baur -) in cultivating the aurea-variety 

 of Antirrhinuui majus. From this form, which is heterozygous, there 

 arc produced green- and aurea-plants in the proportion of 1 : 2, 

 because the yellow individuals formed at the same time die off 

 very young. 



It is clear from the inferior germinating-power of the seed of the 

 white varieties of flax that the gametes-combination of white with 

 white has less vitality. This suggests that very probably the smaller 

 number of seeds is also wholly or partly to be ascribed to the same 

 cause. I have not been able to ascertain whether seed is wanting 

 because fertilisation does not take place at all. It can however be 

 said in general, that the two phenomena, the smaller number ot 

 seeds and their inferior germinating-power, which in the foregoing 

 have been always considered separately, are only the result of 

 a single cause, namely the smaller vitality of the gametes-com- 

 bination of white with white. Only because the death of certain 

 individuals as a result of this cause may take place at diflferent 

 stages of development, two different phenomena can be observed 

 separately. 



I will finally add a few words on a point resulting from these 

 observations. It is found that the number of seeds and their germi- 

 nating-power, therefore the vitality of the gametes-combination, is 

 connected with the colour ot the flowers produced from such seed, 

 that is with the presence or absence of the factor for that colour. 



1) G. Correns, Scheinbare Ausnahmen von der MENDEL'schen Spaltungsregel 

 fur Bastarde. Ber. d. d. bot. Ges. Bd. XX, 1902, p. 159. 



~) E, Baur, Untersuchungen über die Erblichkeitsverhallnisse einer nur in 

 Bastardform lebensfahigen Sippe von Antirrhinum majus. Ber, d. d, bol. Ges. 

 Bd. 25, 1907, p. 442. 



