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Show 60 IPOMCEA PURPUREA. CHAP. II. as those of a wild species growing in a state of nature ; whether the san1e tint occurred, as is probable, in the earlier generations, neither roy gardener nor self could recollect. The flowers on the plants which were first raised fro1n purchased seed, as well as during the first few generations, varied rouch in the depth of the purple tint; roany were roore or less pink, and occasionally a white variety appeared. The crossed plants continued to the tenth generation to vary in the same manner as before, but to a much less degree, owing, probably, to their having become roore or less closely inter-related. We must therefore attribute the extraordinary uniformity of colour in the flowers on the plants of the seventh and succeeding self-fertilised generations, to inheritance not having been interfered with by crosses ·during several preceding generations, in combination with the conditions of life having been very uniform. A plant appeared in the sixth· self-fertilised genera-tion, named the Hero, which exceeded by a little in height its crossed antagonist, and which transmitted its powers of growth and increased self-fertility to its children and grandchildren. A cross between the children of Hero did not give to the grandchildren any advantage over the self-fertilised grandchildren raised from the self-fertilised children. And as far as my observations can be trusted, which were made on very unhealthy plants, the great-grandchildren raised from intercrossing the grandchildren had no advantage over the seedlings from the grandchildren the product of continued self-fertilisation; and what is far more remarkable, the great-grandchildren raised by crossing the grandchildren with a fresh stock, had no advantage over either the intercrossed or self-fertilised great· grandchildren. It thus appears that Hero and its CHAP. II. SUMMARY OF OBSERVATIONS. 61 descendants d I· .u{!{!e re d I. n constitut' · manner from ordina . l Ion In an extraordinary Although the pl:~tp an~s odf the present speciesw . s ra1se c1 un . t generations from crosses b t ~g . en successixe related plants alm t . ~ ween distinct yet inter- . . os Invanably d d . constitutional vigour., anc l 1~ ert.i h. t exthce e· e In heiO'ht 0 ' opponents it has b Y eu self-fertilised b Y I· ntercr'o ssing flo een proved th a t seedli· ngs raised wers on the sam I means superior on th e pant are by no I· n hei. ght and w' ei ht e t contrary. are s~mewhat inferior fertilised with the'~ ' o seedlings raised from flower" u own pollen Th. . ~ fact, which seems t . d' . Is Is a remarkable · o In Icate that 1.r .r .• In some manner m . d c se 1-lertilisation is I ore a vantage h un ess the cross brings with . . ous t an crossj ng' some decided and re on It, as Is generally the case, subject I shall rec!· inp dfetrant advantage; but to this Th a u ure chapt . e benefits h · h er. cross between t: Icl so generally follow from a two differing sor:eJ:ha~ts. apparently depend on the This is shown b th a In. constitution or character 1 Y e seedlinO's f· th . · pants of the ninth . ? rom e Intercrossed pollen from a f h generation, when crossed with h . res stock b . . eight and almost as su .· ~ . ein~ . as superior in mtercrossed plants :;~ror m fertility to the again froro self-fertilised' ;:nt esef l~ter were to seedlings eration. We th l s o t e con·esponding gen us earn th · - ~ere act of crossing t d~ I:Uportant fact that the Ill WO IS tinct pl t h · 1 soroe degree inter-related a d a~ s, w lCh are ?ng subjected to nearl th n whiCh ~ave been little good as compared ~th t~ ~a;e conditrons, does plants belonginO' to d'.(!£! a rom a cross between h · h o Iuerent sto k . .r •• w_ ~c have been subjected t c s or larnllies, and ditlons. We may att 'b o somewhat different con-the crossing of the · n t ute the goo d den.v ed from t . In ercrossed 1 t . en successive generations to th . P. an ~ d~nng the eir still diffenng some- |