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Show CHAP. II. IPOMCEA PURPUREA· 52 d · the right-hand . h other . an Ill competition with eac . f 'the one to the other, the column we have the ratiOS o 1 ts being taken at 100. height of the in~ercrossed ;a:: height of the se~enty- In the bottom hne the ~ h to be 85 · 84 Inches, d 1 ts IS s own . . l three intercrosse p an th ee self-fertilised p ants d that of the seventy- r ~~. 02 inches, or as 100 to 77. TABLE :;-~~surements (in Inches) of Summary OJ 1 • r.l;omrea purpurea. t .L'. the Ten Genera wns. \ Number\ Ave.rage 1\Nfr~;~~:e~:~~g~f~Ratty~~~~::n of Height o e. Selt-fert1- II eight~ o ossed of Crossed f~rtl- . sed Crossed and Number of tbe Generation. ~lants.l Plants. hsedt l;~auts. SE:lf-lcrti\1 cd Plan s. Plants. --- ----:--\----s-\86-00-1----s-\65-"66-\s 100 to 76 "First generat.tOn • • • --Table I. _ ----s-84-1'6-\-----s---\ 66 . 33 as 100 -t7o9 Second generation Table 11. _ -~- - 1-----s----\ 52-~- 8 - . 6 77•41 . 83 as 100 to 6 Third generatiOn· • • Table H-I. ----~- --·~- 6 7 60·14 as 100 to 8 - . 7 69·78 Fourth generatiOn • • _ Table V. -- -~- 75 - ---6- -82·5~4 6 \ 62·33 as 100 to Fifth generation · • • TableVl. ---~- --~- 2 6 \ 63·16 as 100 to 7 - 6 87·50 Sixth generation • • • _ _ Table VII. ---~ 1 --- \ 9 \ 68·25 as 100 to 8 -- 9 83·94 Seventh generation • • _ Table VIII. ---- - . -8- 1-13•2~5 - 8 \ 96•65 \as 100 to 85 Eighth generat10n • • _ Table IX. ---- 9 ---~ 14 I 14 81·39 64·07 \as 100 to 7 Ninth generation ---- Table X. -- 4 - . - 5 93•70 ~-5 \ 50·40 \as 100 to 5 Tenth generatiOn · • __ -~XI. . ---~-~~;~~to 77 Allthetengene1·at1ons\ 73 85·84 73 6b taken together • • f I ----- CHAP. II. SUMMARY OF OBSERVATIONS. 53 The m~an height of the self-fertilised plants in each of the ten generations is also shown in the accompanying diagram, that of the intercrossed plants being taken at 100; and on the right side we see the relative heights of the seventy-three intercrossed plants~ and of the seventy-three self-fertilised plants. The difference in height between the crossed and Diagram showing the mean heights of the crossed and self-fertilised plants of Ipomcea purpurea in the ten generations; the mean height of the crossed plants being taken as 100. On the 1·ight hand, the mean heights of the crossed and self-fertilised plants of all the generations taken together are shown. self-fertilised plants will perhaps be best appreciated by an illustration: If all the men in a country were on an average 6 feet high, and there were some families which had been long and closely interbred, these would be almost dwarfs, their average height during ten generations being only 4 feet 8i inches. |