[E8]

[Darwin's draft letter to Farrer]

[E8v]

651 796

Ch. XII

[illeg]

by some naturalist to species differing in some fundamental manner from the varieties and of course from the individuals of the same species; & this is still the verdict of some naturalist.) (Now the results of my experiments prove that we have a series of results from the in self-fertilisation ing and cross-fertilisation ing of the individuals and or the varieties of the same species, striking by parallel all strikingly analogous with those just given. With the majority of species flowers fertilised with their own pollen yield fewer, sometimes much fewer seeds (Table F & I) than do the flowers are the same plant than those fertilised with pollen from another individual or variety. Some self-fertilised flowers are absolutely sterile; but the degree of their sterility is largely determined by the conditions to which the plants have been exposed, as in the cases of was well exemplified by in the cell of Eschscholtzia & Abutilon. The effects of pollen from the same plant are obliterated by the prepotent influence of pollen from another individual or variety, although the latter may have been placed in th stigma some hours afterwards. The offspring from of self-fertilised flowers are themselves more or less sterile, sometimes highly

[Cross and self fertilisation, pp. 464-5: "Naturalists formerly attributed all these results to the difference between species being fundamentally distinct from that between the varieties of the same species; and this is still the verdict of some naturalists.
The results of my experiments in self-fertilising and cross-fertilising the individuals or the varieties of the same species, are strikingly analogous with those just given, though in a reversed manner. With the majority of species flowers fertilised with their own pollen yield fewer, sometimes much fewer seeds, than those fertilised with pollen from another individual or variety. Some self-fertilised flowers are absolutely sterile; but the degree of their sterility is largely determined by the conditions to which the parent plants have been exposed, as was well exemplified in the case of Eschscholtzia and Abutilon. The effects of pollen from the same plant are obliterated by the prepotent influence of pollen from another individual or variety, although the latter may have been placed on the stigma some hours afterwards. The offspring from self-fertilised flowers are themselves more or less sterile, sometimes highly sterile, and their pollen is sometimes in an imperfect condition; but I have not met with any case of complete sterility in self-fertilised seedlings, as is so common with hybrids."]