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Show 210 ILLEGITIMATE OFFSPRING OF CHAP. v. plan of selecting very :fine capsules ~~ring favourable seasons had been followed for obtaining the normal standards, instead of taking, during various seasons, the first capsules which came to ha~d, the sta~dards would undoubtedly have been considerably higher; and thus the fact of the six foregoing plants appearing to yield an unnaturally high ~erc~ntage of seeds may, perhaps, be explained. ?n this VIew, the~e plants are, in fact, merely fully fertile, and not fertile to an abnormal degree. Nevertheless, a~ char~cters of. all kinds are liable to variation, especially w1th organisms unnaturally treated, and as in the four first and more sterile classes, the plants derived from the same parents and treated in the same manner, certainly did vary much in sterility, it is possible that certain pla~ts in the latter and more fertile classes may have vaned so as to have acquired an abnormal degree of fertilit!' But it should be noticed that, if my standards err m being too low, the sterility of all the many .sterile plants in the several classes will have to be estlm~ted by so much the higher. Finally, we see that the Illegitimate plants in the four first classes are all ~ore or less sterile, some being absolutely barren, with one alone almost completely fertile ; in the three lat.ter classes, some of the plants are moderately s~en~e, whilst others are fully fet·tile, or possibly fertile m excess. The last point which need here be noticed is that, as far as the means of comparison serve, some de??'ee of relationship generally exists between the infertility of the illegitin1ate union of the several parent-forms and that of their illegitimate offspring. Thus t~e two illegitimate unions, from which the plants 1.n Classes VI. and VII. were derived, yielded a fa!r amount of seed, and only a few of these plants are m CHAP. V. HETEROSTYLED TRIMORPHIC PLANTS. 211 any degree sterile. On the other hand, the illegitimate unions between plants of the same form always yiel.d very few seeds, and their seedlings are very stenle. Long - sty led parent-plants when fertilised with pollen from their own-form shortest stamens, ap- · pear to be rather more sterile than when fertilised with their own-form mid-length stamens; and the seedlings from the former union were much more sterile than those from the latter union. In opposition to this relationship, short-styled plants illeo-itimately fertilised with pollen from the mid-length s~amens of the longstyled form (Class V.) are very sterile; whereas some of the offspring raised from this union were far fron1 being highly sterile. It may be added that there is a tolerably close parallelism in all the classes between the degree of sterility of the plants and their dwarfed stat~:e. A~ previous! y stated, an illegitimate plant fert~l~sed with pollen from a legitimate plant has its fertility slightly increased. The importance of the several foregoing conclusions will be apparent at the close of this chapter, when the illegitimate unions between the forms of the same species and their illegitimat~ o~spring, are compared with the hybrid unions of distinct species and their hybrid offspring. 0XALIS. No one has compared the legitimate and illegitim~ te offspring of any trimorphic species in this genus. Hildebrand sowed illegitimately fertilised seeds of O~alis Valdiviana, * but they did not germinate ; and :his _f~ct, as h~ remarks, supports my view that an llegitimate union resembles a hybrid one between * 'Bot. Zeitung,' 1871, p. 433, footnote. p 2 |