OCR Text |
Show 40 IPOMCEA PURPUREA. CHAP. II. the flowers on the self-fertilised plants namely, that most of Th monstrosity consisted In the were somewhat monstrous.l't e that it did not open properly, 'Corolla being irregularly sp I so l'ghtly foliaceous coloured, t f the stmnens s I ' . with one or wo 0 11 I observed this monstrosity and firmly coherent to the coro a.d plants The self-fertilised . fl on the crosse · . In only one ower. ould almost certainly' in a few more plants, ~f well nounshed, ~double flowers, for they had already o·eneratwns have produce bb ecome in s' ome degree sten'l e . * TABLE X (Ninth Generat1'on.) No. ofPot. Crossed Plants. Self-fertilised Plants. Inches. Inches. I. 83~ 57 85~ 71 83~ 48~ ---- - -- II. 83ij 4-5 64ij 43R 64~ 38~ ----- -- III. 79 63 88~ 71 61 89a --- IV. 82 ~ 82a 90 76 ~ v. 89a 67 Crowded plants. 92~ 74-ij 92~ 70 - Total inches. 1139 ·5 897•0 I I -' Crossed and self-fertilised Plants of the Tenth Genera t t· ~1 · -;-- Sitxs Plants were raised in the usual manner from the crosse dpfau of the last generation (Table X.) agai.n I. nt ercross ed ' "a n roml the self-fertilised again self-fertilised. As one of the ~ros~e~ plants in Pot I. in the following tab.le became much dis~as 't having crumpled leaves, and producing hardly any capsu es, I and its opponent have been struck out of the table. * See on this subject' Variation of Animals and Plants under Domestication,' chap. xviii. 2nd edit. vol. ii. p. 152. CHAP. II. FLOWERS ON SAME PLANT CROSSED. 41 TABLE XI. (Tenth Generation.) No. of Pot. Crossed Plants. Self-fertilised Plants. Inches. Inches. I. 92~ 47 g 94~ 34S II. 87 54~ 89 ~ 49 ~ 105 66g Total inches. 468·5 252·0 The five crossed plants average 93 · 7 inches, and the five selffertilised only 50 ·4, or as 100 to· 54. This difference, however, is so great that it must be looked at as in part accidental. The six crossed plants (the diseased one here included) yielded spontaneously 101 capsules, and the six self-fertilised plants 88, the latter being chiefly produced by one of the plants. But as the diseased plant, which yielded hardly any seed, is here included, the ratio of 101 to 88 does not fairly give the relative fertility of the two lots. The stems of the six crossed plants looked so much finer than those of the six self-fertilised plants, that after the capsules had been gathered and most of the leaves had fallen off, they were weighed. Those of the crossed plants weighed 2,693 grains, whilst those of the self-fertilised plants weighed only 1,173 grains, or as 100 to 44; but as the diseased and dwarfed crossed plant is here included, the superiority of the former in weight was really greater. · The Effects on the Offspring of crossing different Flowers on the same Plant, instead of crossing distinct Individuals. -In all the foregoing experiments, seedlings from flowers crossed by pollen from a distinct plant (though in the later generations more or less closely related) were put into competition with, and almost invariably proved markedly superior in height to the offspring from self-fertilised flowers. I wished, therefore, to ascertain whether a cross between two flowers on the same plant would give to the offspring any superiority |