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Show 238 ILLEGITIMATE OFFSPRING OF CHAP. v. an almost exactly intermediate condition in its female organs between the long- and short-styled forms, and consequently, when self-fertilised, yielded a low average of seed. If we add together all the experiments which I made on the equal-styled plants, 41 spontaneously self-fertilised capsules (insects having been excluded) gave an average of 34 seeds, which is exactly tho same number as the parent-plant yielded in Edinburgh. Thirtyfour flowers, fertilised with pollen from the short-styled cowslip (and this is an analogous union), produced 17 capsules, containing an average of 33 · 8 seeds. It is a rather singular circumstance, for which I cannot account, that 20 flowers, artificially fertilised on one occasion with pollen frmn the same plants yielded only ten capsules, containing the low average of 26 · 7 seeds. As bearing on inheritance, it may be added that 72 seedlings were raised from one of the red-flowered, strictly equalstyled, self-fertilised plants descended from the similarly cha. racterised Edinburgh plant. These 72 plants were therefore grandchildren of the Edinburgh plant, and they all bore, as in the first generation, red flowers, with the exception of .one plant, whioh reverted in colour to the common cowslip. In regard to structure, nine plants were truly long-styled and had their stamens seated low clown in the corolla in the proper position; the remaining 63 plants were equal-styled, though the stigma in about a dozen of them stood a little below the anthers. We thus see that the anomalous combination in the same flower, of the male and female sexual organs which properly exist in the two distinct forms, was inherited with much force. Thirty-six seedlings were also raised from long and short-styled common cowslips, crossed with pollen from the equal-styled variety. Of these plants one alone was equal-styled, 20 were short-styled, but with the pistil in three of them rather too long, and the remaining 15 were long-styled.. In this case we have an illustration of the difference between simple inheritance and prepotency of transmission; for the equal-styled variety, when self-fertilised, transmits its character, as we have just seen ' with much force, but when crossed with the com. m.o n cowslip cannot withstand the greater power of transmissiOn of the latter. PULMON ARIA. I have little to say on this genus. I obtained seeds of P. officinalis from a garden where the long-styled form alone grew, CHAP. v. HETEROSTYLED PLANTS. 239 and raised 11 seedlings, which were all long-styled. These plants were named for me by Dr. Hooker. They differed, as has been shown, from the plants belonging to this species which in Germany were experimented on by Hildebrand;* for he found that the long-styled form was absolutely sterile with its own pollen, whilst my long-styled seedlings and the parent-plants yielded a fair supply of seed when self-fertilised. Plants of the longstyled form of Pulmonaria angustijolia were, like Hildebrand's plants, absolutely sterile with their own pollen, so that I could never procure a single seed. On the other band, the shortstyled plants of this species, differently from those of P. o.fficinalis, were fertile with their own pollen in a quite remarkable degree for a heterostyled plant. From seeds carefully self-fertilised I raised 18 plants, of which 13 proved short-styled and 5 long-sty led. POLYGONUM FAGOPYRUM. From flowers on long-styled plants fertilised illegitimately with pollen from the same plant, 49 seedlings were raised, and these consisted of 45 long-styled and 4 short-styled. From flowers on short-styled plants illegitimately fertilised with pollen from the same plant 33 seedlings were raised, and these consisted of 20 short-styled and 13 long-styled. So that the usual l'ule of illegitimately fertilised long-styled plants tending much more strongly than short-styled plants to reproduce their own form here holds good. The illegitimate plants derived from both forms flowered later than the legitimate, and were to the latter in height as 69 to 100. But as these illegitimate plants were descended from parents fertilised with their own pollen, whilst the legitimate plants were descended from parents crossed with pollen from a distinct individual, it is impossible to know how much of their difference in height and period.of flowering, is due to the illegitimate birth of the one set, and how much to the other set being the product of a cross between distinct plants. Concluding Rernarks on the Illegitimate Offspring of Heterostyled Trimorphic and Dirnorphic Plants. It is rmnarkable how closely and in how many points illegitimate unions between the two or three forms of tho * 'Bot. Zeitung,' 186G, p. 13. |