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Show 206 ILLEGITIMATE OFFSPRING OF 011AP. Y. TABLE 30-continued. CLASS IV.-nlegitimate Plants raised from .._7Jfid-styled Parents fertilised with pollen from own-form longest stamens. Minimum Average Num- Average Maximum ber of Seeds, Form. Number of Number in Number of Plant. Number in expressed as Seeds per any one any one the pcrcen tage Capsule. Capsule. Capsule. of the Normal Standard. ------- Plant 18 . Mid-styled. 102·6 131 63 80 " 19 . " 73•4 87 64 56 " 20 . Long-styled 69·6 83 52 75 CLASS V.-lllegitimate Plants raised from Short-styled Parents fertilised with pollen from the mid-length stamens of the longstyled form. Plant 21 • Short-styled 43·0 63 26 52 " 22 . " 100•5 123 86 121 " 23 • " 113·5 123 93 136 " 24 . Long-sty led 82·0 120 67 88 " 2b . . " 122·5 149 84 131 CLASS VI.-nlegitimate Plants raised from Mid-styled Parents fertilised with pollen from the shortest stamens of the longstyled form. Plant 26 • Mid-styled. 86·0 109 61 66 " 27 • . " 99•4 122 53 76 " 28 • " 89·0 119 69 68 29 • Long-styled 100·0 121 77 107 ," 30 • . , 94·0 106 66 101 " 31 • " 90·6 97 79 98 CLASS VII.-Illegitimate Plants raised from Mid-styled Parents fertilised with pollen from the longest stamens of the shortstyled form. - Plant 32 • . Mid-sty led. 127•2 144 96 98 33 • . Short,.styled 113·9 137 90 137 " - CHAP. V. HETEROSTYLED TRIMORPHIC PLANTS. 207 The lessened fertility of most of these illegitimate plants is in many respects a highly remarkable phenomenon. Thirty-three plants in the seven classes were subjected to various trials, and the seeds carefully counted. Some of them were artificially fertilised, but the far greater number were freely fertilised (and this is the better and natural plan) through the agency of insects, by other illegitimate plants. In the right-hand, or percentage column, in the preceding table, a wide difference in fertility between the plants in the first four and the last three classes may be perceived. In the first four classes the plants are descended from the three forms illegitimately fertilised with pollen taken from the same form, but only rarely from the same plant. It is necessary to observe this latter circumstance; for, as I have elsewhere shown,* most plants, when fertilised with their own pollen, or that from the same plant, are in some degree sterile, and the seedlings raised from such unions are likewise in some degree sterile, dwarfed, and feeble. None of the nineteen illegitimate plants in the first four classes were completely fertile ; one, however, was nearly so, yielding 96 per cent. of the proper number of seeds. From this high degree of fertility we have many descending gradations, till we reach an absolute zero, when the plants, though bearing many flowers, did not produce, during successive years, a single seed or even seed-capsule. Some of the most sterile plants did not even yield a single seed when legitimately fertilised with pollen from legitimate plants. There is good reason to believe that the first seven plants in Class I. and II. were the offspring * 'The Effects of Cross and Self-fertilisation in the Vegetable Kingdom,' 1876. |