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Show 200 PETUNIA VIOLACEA. CHAP. VI. 'The \Vesterham-crossed plants in weight to the self-fertilised . as 100 to 22 The W esterham-crossed plants in weight to the intercrossed . as 100 to 101 The intercrossed plants in weight to the self-fertilised . as 100 to 22 · 3 \Ve here see, judging by weight instead of as before by hejght, that the Westerham-crossed and the intercrossed have an immense advantage over the self-fertilised. The Vvesterbamceossed are inferior to tho intercrossed by a mere trifle; but it is almost certain that if they had been allowed to go on growing for another month, the former would have completely beaten the latter. As I had an abundance of seeds of the ·same three lots from which the foregoing plants had been raised, these were s;wn in three long parallel and adjoining rows in the open grounLl, so as to ascertain whether under these circumstances tho results would bo nearly the same as before. Late in the autumn (Nov. 13) the ten tallest plants were carefully selected out of each row and their heights measured, with the following result:- ' TABLE LXXXIII. Petunia violacea. (plants growing in the open ground.). VlestE>rham-crossed I Plants (frum Self- Intercrossed Plants fertili~<'d Plant:- of the (Plants of one ~nd tho St'lf-fertilised Plants Fourth Generation same Stock mter- (Sclf-fcrtiliscu for cro,sed by a fresh crossed for Five Five Generations). Stock). Generations). Inches. Inches. Inches. 34~ 3S 21 a 36g 3Gg 23 35g 39a 25 32~ 37 24~ 37 36 22~ 36~ 41 a 23~ 40~ . 37 ~ 2q 37~ 40 23~ 38~ 41~ 21~ 38~ 36 2q 366•76 382•76 233•13 CHAP. VI. CROSS WITH A FRESH srrOCIL 201 The ten Wester bam-crossed plants here average 36 · 67 inches . in htight; the ten intercrossed plants, 38·27 inches; and the ten self-fertilised, 23 · 31 inches. These three lots of plants were also weighed ; theW ester ham-crossed plants weighed 28 ounces; the intercrossed, 41 ounces; and the self-fertilised, 14 · 75 ounces. We thus got the following ratios:- The Westcr·ham-crossed plants in height to the self-fertilised as 100 to 63 The Wester ham-crossed plants in weight to the self-fertilised . as 100 to 53 The Westerh~tm-crossed plants in height to the intercrossed · as 100 to 104 The Westerham-crossed plants in weight to the intercrossed as 100 to 146 The intercrossed plants in height to the self-fertilised . as 100 to 61 The intercrossed plants in weight to the self-fertilised . as 100 to 36 Here the relative heights of the three lots are nearly the :;:arne (within three or four per cent.) as with the plants in the pots. In weight there is a much greater difference: the Westerhamcrossed exceed the self-fertilised by much less than they did before; but the self-fertilised plants in the pots had become slightly withered, as before stated, and were in consequence unfairly light. The Westerham-crossed plant's are here infArior in weight to the intercrossed plants in a much higher degree than in the pots; and this appeared due to their being much less branched, owing to their having germinated in greater numbers and consequently being much crowded. Their leaves were of a brighter green than those of the intercrossed and self-fertilised plants. Relative Fer·tility of the Three Lots C!f Plants.-None of the plants in pots in the greenhouse ever produced a capsule; and this may be attributed in chief part to the exclusion of nwths. Therefore the fertility of the three lots could be judged of only by that of the plants growing out of doors, which from being left uncovered were probably cross-fertilised. The plants in the three rows were exactly of the same age and had been subjected to closely similar conditions, so that any difference in their fertility must be attributed to their different origin; namely, to tho |