Some did not flower every year; and one plant, behaving in an unprecedented manner, did not flower until three years old. In the two other lots none of the plants grew quite to their full and proper height, as could at once be seen by comparing them with the adjoining rows of legitimate plants. In several plants in all three lots, many of the anthers were either shrivelled or contained brown and tough, or pulpy matter, without any good pollen-grains, and they never shed their contents; they were in the state designated by Gartner as contabescent, which term I will for the future use. (5/2. 'Beitrage zur Kenntniss der Befruchtung' 1844 page 116.) In one flower all the anthers were contabescent excepting two which appeared to the naked eye sound; but under the microscope about two-thirds of the pollen-grains were seen to be small and shrivelled. In another plant, in which all the anthers appeared sound, many of the pollen- grains were shrivelled and of unequal sizes. I counted the seeds produced by seven plants (1 to 7) in the first lot of eight plants, probably the product of parents fertilised by their own-form shortest stamens, and the seeds produced by three plants in the other two lots, almost certainly the product of parents fertilised by their own-form mid-length stamens.

[PLANT 1.

This long-styled plant was allowed during 1863 to be freely and legitimately fertilised by an adjoining illegitimate mid-styled plant, but it did not yield a single seed-capsule. It was then removed and planted in a remote place close to a brother long-styled plant Number 2, so that it must have been freely though illegitimately fertilised; under these circumstances it did not yield during 1864 and 1865 a single capsule. I should here state that a legitimate or ordinary long-styled plant, when growing isolated, and freely though illegitimately fertilised by insects with its own pollen, yielded an immense number of capsules, which contained on an average 21.5 seeds.

PLANT 2.

This long-styled plant, after flowering during 1863 close to an illegitimate mid-styled plant, produced less than twenty capsules, which contained on an average between four and five seeds. When subsequently growing in company with Number 1, by which it will have been illegitimately fertilised, it yielded in 1866 not a single capsule, but in 1865 it yielded twenty-two capsules: the best of these, fifteen in number, were examined; eight contained no seed, and the remaining seven contained on an average only three seeds, and these seeds were so small and shrivelled that I doubt whether they would have germinated.

PLANTS 3 AND 4.

These two long-styled plants, after being freely and legitimately fertilised during 1863 by the same illegitimate mid-styled plant as in the last case, were as miserably sterile as Number 2.

PLANT 5.

This long-styled plant, after flowering in 1863 close to an illegitimate mid- styled plant, yielded only four capsules, which altogether included only five seeds. During 1864, 1865, and 1866, it was surrounded either by illegitimate or legitimate plants of the other two forms; but it did not yield a single capsule. It was a superfluous experiment, but I likewise artificially fertilised in a legitimate manner twelve flowers; but not one of these produced a capsule; so that this plant was almost absolutely barren.

PLANT 6.

This long-styled plant, after flowering during the favourable year of 1866, surrounded by illegitimate plants of the other two forms, did not produce a single capsule.

PLANT 7.

This long-styled plant was the most fertile of the eight plants of the first lot. During 1865 it was surrounded by illegitimate plants of various parentage, many of which were highly fertile, and must thus have been legitimately fertilised. It produced a good many capsules, ten of which yielded an average of 36.1 seeds, with a maximum of 47 and a minimum of 22; so that this plant produced 39 per cent of the full number of seeds. During 1864 it was surrounded by legitimate and illegitimate plants of the other two forms; and nine capsules (one poor one being rejected) yielded an average of 41.9 seeds, with a maximum of 56 and a minimum of 28; so that, under these favourable circumstances, this plant, the most fertile of the first lot, did not yield, when legitimately fertilised, quite 45 per cent of the full complement of seeds.]

In the second lot of plants in the present class, descended from the long-styled form, almost certainly fertilised with pollen from its own mid-length stamens, the plants, as already stated, were not nearly so dwarfed or so sterile as in the first lot.

Charles Darwin

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