UBER MUTMASSLICHE PARTIELLE HETEROGAMIE 73 

shown by Saunpers (1911) in the case of white-cream plastids in 
Matthiola. In the first case (Aa) there is a reduplication of A-ovules 
and a-pollen (see scheme I, p. 26), in the second case (aA), conversely, 
a majority of a-ovules and A-pollen is formed (see scheme II, p. 26). 
The aA-heterozygotes give riso to B-speltoid-series, with great abun- 
dance of heterozygotes (see scheme VI, p. 45). The Aa-heterozygotes 
should also give a progeny with abundance of heterozygotes (see scheme 
I, p. 26), were it not for the simultaneous elimination of a-pollen 
(see scheme V, p. 45). This elimination of a-pollen may surpass the 
reduplication of a-pollen, and in this case there must be a majority 
of A-ovules and of fertilizing A-pollen, resulting in a larger number of 
normal plants than of heterozygotes in the C-series (Chapter IH, D). 
5. In Chapter III, A and B is also shown, why elimination of 
male (or female) gametes alone cannot account for the numerical 
aberrations in the B- and C-series. In Chapter III, D it is conversely 
shown, why heterogamy alone without elimination does not suffice 
for elucidating the facts, and why heterogamy in these cases must be 
suggested to exist in both sexes and not in the male sex only (as in 
the case of Saunpers’ Matthiola). The supposition of common redu- 
plication of A- or a-gametes in the same sense by ovules and pollen 
in a heterozygote is rejected. 
6. The system of heterogamous reduplication found in the aA- 
heterozygotes seems to be 1:4 or in one speltoid-series (tab. 9) 1: 5. 
The system in the Aa-heterozygotes does not seem to be the same, but 
further investigations on this point are necessary (Chapter III, G). 
7. In Chapter IV the suggested heterogamy in wheat-speltoids is 
discussed in connexion with previously found cases of heterogamy in 
Matthiola (SauNDers), Campanula (PELLEW), Begonia (BATESON and 
SuTToN) and Oenothera (DE Vries, RENNER, HERIBERT-NILSSON). In 
Matthiola the author holds the same view as Saunpers, that with re- 
gard both to the allelomorph white-blue plastids and the allelomorph 
single-double the differential distribution to ovules and pollen is due to 
heterogamy and not to physiological elimination of male gametes. The 
heterogamy found in wheat is characterized as partial and of an 
unusually low degree existing (at least mostly) in both sexes. 
The simultaneous existence in wheat of several gametic (and zygotic) 
complications (heterogamy, elimination of gametes etc.), which give 
rise to very aberrant types of segregation is in accordance with the 
suggestion of Herrpert-Ni_sson (1915, 1920 c) that the peculiar genetic 
behavior of Oenothera finally is caused by complications of mostly 
