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Show 232 ILLEGITIMATE OFFSPRING OF CUAP. v. legitimate plants so1netimes yield. But this high average was almost certainly false; and I mention tho case for the sake of showing the difficulty of arriving at a fair result ; for this average mainly depended on two capsules containing the extraordinary numbers of 75 and 56 seeds; these seeds, however, though I felt bound to count them, were so poor that, judging from trials made in other cases, I do not suppose that one would have germinated; and therefore they ought not to have been included. Lastly, 20 floweTs were legitimately feTtilised with pollen fTom a legitimate plant, and this incTeased their fertility; foT they produced 10 capsules. Yet this is but a very s1nall proportion for a legitimate union. There can, therefore, be no doubt that those :five long-styled plants and the one short-styled plant of the first illegiti1nate generation were extremely sterile. Their sterility was shown, as in the case of hybrids, in another way, namely, by their flowering profusely, and especially by the long endurance of the flowers. For instance, I fertilised many flowers on these plants, and fifteen days afterwards (viz. on March 22nd) I fertilised numerous long-styled and short-styled flowers on common cowslips growing close by. These latter flowers, on A. pril 8th, were withered, whilst most of the illegitimate flowers remained quite fresh for several days subsequently ; so that some of these illegitimate plants, after being fertilised, remained in full bloom for above a month. We will now turn to the fertility of the 53 illegitimate long-styled grandchildren, descended from the long-styled plant which was first fertilised with its own pollen. The pollen in two of these plants included a multitude of small and shrivelled grains. Nevertheless they were not very sterile ; for 25 flowers, fer- CHAP, V. HETEROSTYLED DIMORPHIC PLANTS. 233 tilised with their own" pollen, produced 15 capsules, containing an average of 16 · 3 seeds. As already stated, the probable average with legitimate plants for a union of this nature is rather above 20 seeds. These plants were remarkably healthy and vigorous, as long as they were kept under highly favourable conditions in pots in the greenhouse ; and such treatment greatly increases the fertility of the cowslip. When these same plants were planted during the next year (which, however, was an unfavourable one), out of doors in good soil, 20 self-fertilised flowers produced only 5 capsules, containing extremely few and wretched seeds. . Four long-styled great-grandchildren were raised from the self-fertilised grandchildren, and were kept under the same highly favourable conditions in the greenhouse; 10 of their flowers were fertilised with own-form pollen and yielded the large proportion of 6 capsules, containing on an average 18 · 7 seeds. From these seeds 20 long-sty led great-great-grandchildren were raised, which were likewise kept in the greenhouse. Thirty of their flowers were fertilised with their own pollen and yielded 17 capsules, containing on an average no less than 32, mostly fine seeds. It appears, therefore, that the fertility of these plants of the fourth illegitimate generation, as long as they were kept under highly favourable conditions, had not decreased, but had rather increased. The result, however, was widely different when they weTe planted out of doors in good soil, where other cowslips grew vigorously and were completely fertile ; for these illegitimate plants now became much dwarfed in stature and extremely sterile, notwithstanding that they were exposed to the visits of insects, and must have been legitimately fertilised by the surrounding legitimate plants. A whole |