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Show IPOM<EA PURPUREA. CnA1~. n. 30 at the final measuring. But it is an interesting fact, of which I have seen several other instances, that one of the self-fertilised plant~. when nearly a foot in height, was half an inch taller than the crossed plant; and again, when two feet high, it was 1~ of an inch taller, but during the ten subsequent days the crossed plant began to gain on it~ antagonist, and ever afterward asserted its supremacy, until it exceeded its self-fertilised opponent by 16 Tinhceh feisv.e crossed plants in Pots I. and II. were covered with -a net, and produced 121 capsules; the five self-fertilised plants produced eighty-four capsules, so that the numbers of capsules were as 100 to 69. Of the 121 capsules on the crosseU plants sixty-five were tl1e product of flowers crossed with pollen from a distinct plant, and these contained on an averrtge 5 · 23 seeds per capsule; the remaining fifty-six capsules were spontaneously self-fertilised. Of the eighty-four capsules on the self-fertilised plants, all the product of renewed self-fertilisation, fifty-fi"e (which were alone examined) contained on an averao-e 4 · 85 seeds per capsule. Therefore the cross-fertilised capsule~, compared with the self-fertilised capsules, yielded seeds in the proportion of 100 to 93. The crossed seeds were relatively heavier than the self-fertilised seeds. Combining the above data (i.e., number of capsules and average number of contained seeds), the crossed plants, compared with the self-fertilised, yielded seeds in the ratio of 100 to 64. These crossed plants produced, as already stated, flfty-six spontaneously self-fertilised capsules, and the self-fertilised plants produced twenty-nine such capsules. The forn1er contained on an average, in comparison with the Jattcr, seeds in the proportion of 100 to 99. In Pot III., on the opposite sides of which a large number of crossed and self-fertilised seeds had been sown and the seedlings allowed to struggle together, the crossed plants bad at ftrst no great advantage. At one time tho tallest crossed wn,s 25!; inches high, and the tallest self-fertilised plants 21i - But the difference afterwards becn,me much greater. The plants on both sides, from being so crowded, were poor specimens. Tho flowers were allowed to fertilise themselves spontaneously under a net; the crossed plants produced thirty-seven capsules, the self-fertilised plants only eighteen, or as 100 to 4 7. The former contained on an average 3 · 62 seeds per capsule; and the latter 3 · 38 seeds, or as 100 to 93. Combining these data (i.e., number CHAP. II. CROSSED AND SELF-FERTILISED PLA of capsules and NTS. 31 I t average number f d fo a~; produced seeds compared ow: s), the crowded crossed h d. These latter seeds how the self-fertrhsod as 100 un red weighing 41. 64 ' . ever, were decidedly he . on the crossed plants of ~:ams, than those from the :._vier,! a and this probably w'as dw wh a hundred weighed 36.79 psu os :~lf;f~~tilised plants havi:; :~e~h:e:~wer capsules borne g:;'~~~ u:de :crossed plants in this the firs~r ~ounshed. We thus see abl r avourable conditions, and wh generation, when grown h . c conditiO~s from being much en grown under unfavour- m:l:,ht, and m the number of ca crolwded, greatly exceeded in In e number of seeds er psu cs produced, and sli()'h Fl Grossed and srif-fertiEsed cj;!~le, the self-fertilised plant~. tly owers on the crossed I ts of the Second G eneratio ;er~ crossed by pollen f!~n1~s~;;~e l:st generation (Tab!:·I.) wn' and flowers o th c pants of the sam pollen from th n e self-fertilised plants we ' ~ genora-t t e Saine flower Th re. lertihsed by threea eel Ii n every t·cspect as b· eforee as eeid s th. u s pro d need were resu t. ' nc we have in ·Table II. TABLE II. (Se con d Generat/on.) No. of Pot. I. . II. Cro~scd Plants. Inches. 87 8:~ 83 505 Inches. 67~ 68~ 803 398 . H.e re agai n every si.n gle crossed I . gonist. The self-fertilised plant .P apnt Is taller than its anta tr e1a1c hed the unusual height ofc 80<· In. I ot I ., wh I·c h ultimately-i: er than the opposed crossed ia~~tc Ies, was for a long time .. The average height of the sip ' though at last beaten b :shliiOsOt ttoha 7t9.o f the six self-fertili~e~opslsane dst p1l~s nt6s6 i s· 3834 ··1 6 hi nche:' a ~~m fromr ossed and .s ez(/r_-..;p e r t t· zt· seJ Plants of th . ' the crossed plants of the last e Th?.r.d Generation.-Seecls gencratwn (Table II.) ag.a.:m |
