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Show 200 ILLEGITIMATE OFFSPRING OF CHAP. v. case, as in some previous cases, pollen from legitimate plants added in a small degree to the fertility of the plant; and tho fertility would, perhaps, have been still greater had not the summer of 1b64 been very hot and certainly unfavourable to some of the plants of Lythrum. PLant 23. This short-styled plant produced perfectly sound pollen. During 1866 it was freely and legitimately fel'tilised by the other illegitimate plants specified under the last experiment, and eight capsules yielded an average of 113 · 5 seeds, with a maximum of 123 and a minimum of 93. Hence this plant exceeded the normal standard, producing no less than 136 per cent. of seeds. Plant 24. This long-styled plant produced pollen which seemed under the microscope sound; but some of the grains did not swell when placed in water. During 1864 it was legitimately fertilised by legitimate and illegitimate plants in the same manner as Plant 22, but yielded an average, from ten capsules, of only 55 seeds, with a maximum of 88 and a minimum of 24, thus attaining 59 per cent. of the normal fertility. This low degree of fertility, I presume, was owing to the unfavourable season; for during 1866, when legitimately fertilised by illegitimate plants in the manner described under No. 22, it yielded an average, from eight capsules, of 82 seeds, with a maximum of 120 and a minimum of 67, thus producing 88 per cent. of the normal number of seeds. Plant 25. The pollen of this long-styled plant contained a moderate number of poor and shrivelled grains; and this is a surprising circumstance, as it yielded an extraordinary number of seeds. During 1866 it was freely and legitimately fertilised by illegitimate plants, as described under No. 22, and yielded an average, from eight capsules, of 122:5 seeds, with a maximum of 149 and a minimmn of 84. Hence this plant exceeded the normal standard, producing no less than 131 per cent. of seeds. CLASS VI. Illegitimate Plants raised frmn Mid-styled Parents fertilised with pollen from the shortest stamens of the long-styled form. I raised from this union twenty-:five plants, which proved to be seventeen long-styled and eight mid- CuAr. V. HETEROSTYLED TRil\iORPHIC PLANTS. 201 styled, but not one short-styled. Non.e of thes~ plants were in the least dwarfed. I examined, dunng the highly favourable season of 1866, the pollen of four plants: in one mid-styled plant, some of the anthers of the longest stamens were contabescent, but the pollengrains in the other anthers were mostly sound, as they were in all the anthers of the shortest stamens; in two other mid-styled and in one long-styled plant many of the pollen-grains were small and shrivelled; and in the latter plant as many as a :fifth or sixth part appeared to be in this state. I counted the seeds in five plants (Nos. 26 to 30), of which two were moderately sterile and three fully fertile. Plant 26. This mid-styled plant was freely and legitimately fertilised, during the rather unfavourable year 1864, by numerous surrounding legitimate and illegitimate plants. It yielded an average, from ten capsules, of 83 · 5 seeds, with a maximum of 110 and a minimum of 64, thus attaining 64 per cent. of the normal fertility. During the highly favourable year 1866, it was freely and legitimately fertilised by illegitimate plants belonging to the present Class and to Class V., and yielded an average, from eight capsules, of 86 seeds, with a maximum of 109 and a minimum of 61, and thus attained 66 per cent. of the normal fertility. This was the plant with some of the anthers of the longest stamens con tabescent as above mentioned. Plant 27. This mid-styled plant, fertilised during 1864 in the same manner as the last, yielded an average, from ten capsules, of 99·4 seeds, with a maximum of 122 and a minimum of 53, thus attaining to 76 per cent. of the nonnal fertility. If the season had been more favourable, its fertility would probably have been somewhat greater, but, judging from the last experiment, only in a slight degree. Plant 28. This mid-styled plant, when legitimately fertilised during the favourable season of 1866, in the manner described under No. 26, yielded an average, from eight capsules, of 89 seeds, with a maximum of 119 and a minimum of 69, thus producing 68 per cent. of the full number of seeds. In the pollen of both sets of anthers, nearly as many grains were small and shrivelled as sound. |