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Show 70 MIMUL U8 J, UTE US. CnAP. III. carefully. The self-fertilised seedlings came up rather before the crossed but both lots were for a time of equal height. When first measur~d, the average hdght of the six tallest crossed pla~t~ in the three pots was 7 · 02, and that of the ~ix tallest self-fertlll scd pl::tnts 8 · ~7 inches, or as 100 to 128. When fully grm~n the same plants were again measured, with the result shown 111 the following table:- TABLE XVIII. (Se venth Generation.) No. of Pot. I. 1------- II. Crossed Plants. \ Self-f~rtHised Plants. lncbes. 11 ~ 11~ 12 ~ 11 ~ Inc h e;;. 1 9~ 18 1 8~ 1 4~ - -----[---- ---- - -------- III. 1~! _!_ ---~~R Total inches. sa·63 I 93 ·88 The average height of the six crossed is here 11· 43, and that of the six self-fertilised 15 · 64, or as 100 to 137. As it was now evident that the tall white variety transmitted its characters faithfully, and as the self-fertilised plants consisted exclusively of this variety, it was manifest that they would · always exceed in height the crossed plants which belonged chiefly to the original shorter varieties. This line of experiment was therefore discontinued, and I tried whether intercrossing two self-fertilised plants of the sixth generation, growing in distinct pots, w:ould give their offspring any advantage over the .Offspring of flowers on one of the same plants fertilised with their own pollen. These latter seedlings formed the seventh generation of self-fertilised plants, like those in the right-hand column in Table XVIII.; the crossed plants were the product of six previous self-fertilised generations with an intercross in the la-st generation. The seeds were allowed to germinate on sand, and were planted in pairs on opposite sides of four pots, all the ;remaining seeds being sown crowded on opposite sides of Pot V. in Table XIX.; the three tallest on each side in this latter pot .being alone measured. All the plants were twice measured- the first time w hi1st young, and the average height of the crossed plants CHAP. nr cnoss . ED AND SELF-FERTILISED PLANTS. 71 . to tha.t of the self-fertilised was then as 1 grown they were aO'ain meas d . 00 to 122. When fully e< . ure ' as Ill the following table:- TABLE XIX I No. of Pot. I_ntercrossed Plants from Self-fertilised Self-!ertillsed Plants Plants of the Si.xth of the Seventh Genera tion. Generation. -- ---- -- -· Inches. I. 12s ln~h cs . 15 § 1 0~ llg 10 11 14 ~ 11 ---- ---- -- II. 10§ ------ 11 ~ 7H 11 ~ 12d 8 ~ 7 14 ~ - III. --- 13 ~ 10 ~ 12§ ---- us ---- IV. 71 - g 14 ~ 8 ~ 7 72 ij 8 V. 8 ~ - Crowded. 10§ 9 9:J 8§ g ,_ 92g Total in inches. --- L 159·38 I - 175 •50 The average height of th . t . 9. 96 inches, and that of th e .sit eon Interc~~ssed plants is here as 100 to 110. so that th ~ Stlx een self-fertilised plants 10.96 or h . ' e 111 ercrossed pla t th · ' w ICh had been self.(' t'l' d fi 11 s, e progenitors of' d -1er 1 1se or th · . an had been exposed durin . th e si:r prevwus generations, form condition~, were some,; hat ei;~~le t~me t.o remarkably uniof the seventh self-fertilised t· or In hmght to the plants sently s.ee that a similar expe;:~~~ wn. But as· we shall pregeneratiOns of self-fertilisatio ., mad~. after two additional . not how far to t.rust the .n gave a different result, I know pots in Table XIX pr.e~ent one. In three of the five the· other two a cro~:e;eli-fe~·tlhsed plant flowered first, and in l'em-arkably fertile for t ant. :fl Those self-fertilised plants wero pollen produced n~ less ~~en y . owers fertilised with their own an mneteen v~ry fine capsules ! |