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Show 308 UNIFORM COLOUR OF THE FLOvVERS CHAP. VIII. thorn; and the flo,wers on the several. intercrossed :t->lants of the ninth generation differed considerably in colour. On the other hand, the uniformity in colour of the flowers on the plants of all the later self-fertilised generations was quite surprising; on a casual inspection they might have been said to be quite alike, but the crimson blotches were not of exactly the same shape, or in exactly the same position. Both my gardener and 1nyself believe that this variety did not appear amongst the parent-plants, raised from purchased seeds, but from its appearance amongst both the erossed and self-fertilised plants of the third and fourth generations; and fron1 what I have seen of the variation of this species on other occasions, it is probable that it would occasionally appear under any circumstances. vV e learn, however, from the present case that under the peculiar conditions to which my plants were subjected, this particular variety, ren1arkable for its colouring, largeness of the corolla, and increased height of the whole plant, prevailed in the sixth and all the succeeding self-fertilised generations to the complete exclusion of every other variety . . Ipoma3a purpurea.-1\iy attention was first drawn to the present subject by observing that the flowers on all the plants of the seventh self-fertilised generation were of a uniform, ren1arkably rich, dark purple tint. The 1nany plants which were raised during the three succeeding generations, up to the last or tenth, all produced flowers coloured in the sa1ne manner. They were absolutely uniform in tint, like those of a constant species living in a state of nature; and the self-fertilised · plants might have been distinguished with certainty, as 1ny gardener remarked, without the aid of labels, from the intercrossed plants of the later generations. rrhese, however, had mor.e uniformly coloured flowers CHAP. VIII. ON SELF-FERTILISED PLANTS. 309 than those .which were first raised from the purchased seeds. This dark purple variety did not appear, as far as my gardener and myself could recollect before the fifth or sixth self-fertilised generation. }lowever this may have been, it became, thr0110'h continued self-fertili~ation and .. the cultivation of' the plants under. un1form conditions, perfectly constant, to the· exclus1on of every other variety. Dian_thus caryop~yllus.-The self-fertilised plants of the thud generation all bore flowers of exactly the sa~e pale rose-~olour; and in this respect they differecl quite remarkably fro1n the plants growin()' in a large bed close by and raised from seeds purchas~d fro1n tbe same nursery garden. In this case it is not improbable that some of the parent plants which were first selffertilised may have borne flowers thus coloured; but a_s se~er~l plants were self-fertilised in the first generation, It IS extremely improbable that all bore :flowerR of exactly the same tint as those of the self-fertilise(l plants o! tl:e third generation. The. intercrossed plants of the th1rd generation likewise produced flowers almost, though not quite so uniform in tint as those of the self-fertilised plaH.ts. . . Petunia violacea.-In this case I happened to reconl In my notes that the flowers on the parent-plant which was first self-fertilised were of a "dingy purple colour." In the fifth self-fertilised generation, every one of the twenty-one self~fertilised plants growing in pots, an(l all the many plants in a long row out of doors, produced flowers of absolutely the same tint, namely, of a dull, rather peculiar and ugly flesh colour; therefor~, considerably unlike those on the parent-plant. I beheve that this change of colour supervened quite ~radually; but I kept no record, as the point did not Interest me until I was struck with the uniform tint |