In regard to the long-styled plants, their illegitimate offspring, of which fifty-two were raised in the course of two generations, were all long-styled. (5/7. Dr. Hildebrand, who first called attention to this subject 'Botanische Zeitung' 1864 page 5, raised from a similar illegitimate union seventeen plants, of which fourteen were long-styled and three short-styled. From a short-styled plant illegitimately fertilised with its own pollen he raised fourteen plants, of which eleven were short-styled and three long-styled.) These plants grew vigorously; but the flowers in one instance were small, appearing as if they had reverted to the wild state. In the first illegitimate generation they were perfectly fertile, and in the second their fertility was only very slightly impaired. With respect to the short-styled plants, twenty-four out of twenty- five of their illegitimate offspring were short-styled. They were dwarfed in stature, and one lot of grandchildren had so poor a constitution that four out of six plants perished before flowering. The two survivors, when illegitimately fertilised with their own-form pollen, were rather less fertile than they ought to have been; but their loss of fertility was clearly shown in a special and unexpected manner, namely, when legitimately fertilised by other illegitimate plants: thus altogether eighteen flowers were fertilised in this manner, and yielded twelve capsules, which included on an average only 28.5 seeds, with a maximum of 45. Now a legitimate short-styled plant would have yielded, when legitimately fertilised, an average of 64 seeds, with a possible maximum of 74. This particular kind of infertility will perhaps be best appreciated by a simile: we may assume that with mankind six children would be born on an average from an ordinary marriage; but that only three would be born from an incestuous marriage. According to the analogy of Primula Sinensis, the children of such incestuous marriages, if they continued to marry incestuously, would have their sterility only slightly increased; but their fertility would not be restored by a proper marriage; for if two children, both of incestuous origin, but in no degree related to each other, were to marry, the marriage would of course be strictly legitimate, nevertheless they would not give birth to more than half the full and proper number of children.

[EQUAL-STYLED VARIETY OF Primula Sinensis.

As any variation in the structure of the reproductive organs, combined with changed function, is a rare event, the following cases are worth giving in detail. My attention was first called to the subject by observing, in 1862, a long-styled plant, descended from a self-fertilised long-styled parent, which had some of its flowers in an anomalous state, namely, with the stamens placed low down in the corolla as in the ordinary long-styled form, but with the pistils so short that the stigmas stood on a level with the anthers. These stigmas were nearly as globular and as smooth as in the short-styled form, instead of being elongated and rough as in the long-styled form. Here, then, we have combined in the same flower, the short stamens of the long-styled form with a pistil closely resembling that of the short-styled form. But the structure varied much even on the same umbel: for in two flowers the pistil was intermediate in length between that of the long and that of the short-styled form, with the stigma elongated as in the former, and smooth as in the latter; and in three other flowers the structure was in all respects like that of the long-styled form. These modifications appeared to me so remarkable that I fertilised eight of the flowers with their own pollen, and obtained five capsules, which contained on an average 43 seeds; and this number shows that the flowers had become abnormally fertile in comparison with those of ordinary long- styled plants when self-fertilised. I was thus led to examine the plants in several small collections, and the result showed that the equal-styled variety was not rare.

Charles Darwin

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