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Show 236 ILLEGITIMATE OFFSPRING OF CHAP. V. with a few shrivelled grains. In function this pollen was identical with that of the short-styled cowslip; for ton lonO'styled flowers of the common cowslip, legitimately fertilis~d with pollen .fr?m a true equal-styled variety, produced six capsules, conta1mng on an averag~ 3~ · 4 ~e.eds; whilst seven capsules on a short-styled cowshp Illegitimately fertilised with pollen from the equal-styled variety, yielded an average of only 14·5 seeds. As the equal-styled plants differ from one another in their powers of reproduction,. and as this is an important subject I will give a few details with respect to five of them. First, a~ equal-styled plant, protected from insects (as was dono in all the following cases, with one stated exception), spontaneously produced numerous capsules, five of which gave an average of 44 · 8 seeds, with a maximum in one capsule of 57. But six capsules, the product of fertilisation with pollen from a shortstyled cowslip (and this is a legitimate union), gave an average of 28 · 5 seeds, with a maximum of 49; and this is a much lower average than might have been expected. Secondly, nino capsules from another equal-styled plant, which had not been protected from insects, but probably was self-fertilised, gave an average of 45 · 2 seeds, with a maximum of 58. Thirdly, another plant which had a very short pistil in 1865, produced spoutaneously many capsules, six of which contained an average of 33 · 9 seeds, with a maximum of 38. In 1866 this same plant had a pistil of wonderful length; for it projected quito above the anthers, and the stigma resembled that of the long-styled form. In this condition it produced spontaneously a vast number of fine capsules, six of which contained almost exactly the same average number as before, viz. 34 · 3, with a maximum of 38. Four flowers on this plant, legitimately fertilised with pollen from a short-styled cowslip, yielded capsules with an average of 30 · 2 seeds. Fourthly another short-styled plant spontaneously produced in 1865 an abundance of capsules, ten of which contained an average of 35 · 6 seeds, with a maximum of 54. In 1866 this same plant had become in all respects longstyled, and ten capsules gave almost exactly the same average as before, viz. 35 ·1 seeds, with a maximum of 47. Eight flowers on this plant, legitimately fertilised with pollen from a short-styled cowslip, produced six capsules, with the high average of 53 seeds, and the high maximum of 67. Eight flowers were also fertilised with pollen from a long-styled cow- CnAP. V. HETEROSrrYLED DIMORPHIC PLANTS. . 237 slip (this being an illegitimate union), and produced seven capsules, containing an average of 24·4 seeds, with a maximum of 32. The fifth and last plant remained in the same condition during both years: it had a pistil rather longer than that of the true short-styled form, with the stigma smooth, as it ought to be in this form, but abnormal in shape, like a much-elongated inverterr cone. It produced spontaneow~ly many capsules, five of which, in 1B65, gave an average of only 15 · 6 Reeds; and in 1866 ten capsules still gave an average only a little higher, viz. of 22 ·1, with a maximum of 30. Sixteen flowers were fertilised with pollen from a long-styled cowslip, and pro luced12 capsules, with an average of 24 · 9 seeds, and a 1naximum of 42. Eight flowers were fertilised with pollen from a short-styled cowslip, but yielded only two capsules, containing 18 and 23 seeds. Hence this plant, in flulction and 11artially in stTucture, was in an almost exactly intermediate state between tho longstyled and short-styled form, but inclining towards the shortstyled; and this accounts for the low average of seeds which it produced when spontaneouRly self-fertilised. The foregoing five plants thus differ much from one another in the nature of their fertility. In two individuals a great difference in the length of the pistil during two succeeding years made no difference in the number of seeds produced. As all five plants possessed the n1ale organs of the short-styled form in a perfect state, and the female organs of the long-styled fonn in a more or less complete state, they spontaneously produced a surpri. ing number of capsules, which generally contained a large average of remarkably fine seeds. With ordinary cowslips, ler;itimately fertilised, I once obtained from plants cultivated in the green-house the high average, from seven capsules, of 58· 7 seeds, with a maximum in one capsule of 87 seeds; but from plants grown out of doors I never obtained a higher average than 41 seeds. Now two of the equal-styled plants, grown out of doors and spontaneously self-fer·tilised, gave averages of 44 and 45 seeLls; but this high fertility may perhaps be in part attributed to the stigma receiving pollen from the surrounding anthers at exactly the right period. 'l'wo of these plants, fertitisod with poHen from a short-styled cowslip (and this in fact is a legitimate union), gave a lower average than when solf-fortilisocl. On the other hand, another plant, when similarly fertilised. by a cowslip, yielded the unusually high average of 53 seeds, with a maximum of 67. Lastly, as we have just seen, one of these l)lants was in |