310 Strasburger. — The Periodic Reduction of 
peloric Snapdragon ( Antirrhinum majus ) described by Charles 
Darwin 1 . The seed produced by the peloric plants when 
fertilized with their own pollen yielded only peloric indi- 
viduals : whilst the seed produced by peloric plants fertilized 
with the pollen of the normal forms yielded only normal 
plants ; and similarly the seed produced by plants of the 
normal form fertilized with pollen from the peloric form 
yielded only normal plants. Hence the influence of those 
chromosomes which induced the peloric condition was, in the 
two latter cases, neutralized by the chromosomes of the normal 
form. But the peloric chromosomes were not destroyed, for 
the descendants of the normal plants of semi-peloric origin 
were peloric to the extent of one-third. 
However peculiar may be the mixture of the parental 
characters which a hybrid presents, it is repeated in all hybrids 
having the same origin. But this is not the case with the 
offspring of hybrids fertilized with their own pollen : on the 
contrary, the progeny is now remarkable for a high degree of 
variability. In successive generations resulting from repeated 
fertilizations with their own pollen, there is a growing tendency 
to revert to the parental forms. But few hybrids, fertilized 
with their own pollen, continue to reproduce themselves 
unchanged, and thus practically constitute new species. 
Weismann 2 endeavours to account for the variability of the 
offspring of hybrids by referring it to divisions accompanied 
with reduction, in the development of the sexual cells: 
these reducing divisions result in dissimilar products, and the 
union of the dissimilar products induces variability. This 
explanation is, however, inadmissible because, as a matter of 
fact, such divisions do not take place among plants : the 
causes of the variability of hybrids must be sought elsewhere. 
They are to be looked for in those processes which lead to 
1 Das Variiren der Thiere und Pflanzen im Zustande der Domestication, 
Germ, ed., 1868, Bd. II, p. 92 : Variation of Animals and Plants under 
Domestication, ii, pp. 70, 93, 1868. 
2 Das Keimplasma, eine Theorie der Vererbung, 1892, p. 293: Engl. Ed., 
p. 299. 
