Column 3: self-fertilised Plants (self-fertilised for five generations).
34 2/8 : 38 : 27 3/8. 36 2/8 : 36 2/8 : 23. 35 2/8 : 39 5/8 : 25. 32 4/8 : 37 : 24 1/8. 37 : 36 : 22 4/8. 36 4/8 : 41 3/8 : 23 3/8. 40 7/8 : 37 2/8 : 21 5/8. 37 2/8 : 40 : 23 4/8. 38 2/8 : 41 2/8 : 21 3/8. 38 5/8 : 36 : 21 2/8.
366.76 : 382.76 : 233.13.
The ten Westerham-crossed plants here average 36.67 inches in height; the ten intercrossed plants, 38.27 inches; and the ten self-fertilised, 23.31 inches. These three lots of plants were also weighed; the Westerham-crossed plants weighed 28 ounces; the intercrossed plants, 41 ounces; and the self-fertilised, 14.75 ounces. We thus get the following ratios:--
The Westerham-crossed plants in height to the self-fertilised as 100 to 63.
The Westerham-crossed plants in weight to the self-fertilised as 100 to 53.
The Westerham-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 same (within three or four per cent) as with the plants in the pots. In weight there is a much greater difference: the Westerham-crossed 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 plants are here inferior 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 FERTILITY OF THE THREE LOTS OF 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 moths. 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 the one lot being derived from plants self-fertilised for four generations and then crossed with a fresh stock; to the second lot being derived from plants of the same old stock intercrossed for five generations; and to the third lot being derived from plants self-fertilised for five generations. All the capsules, some nearly mature and some only half-grown, were gathered, counted, and weighed from the ten finest plants in each of the three rows, of which the measurements and weights have already been given. The intercrossed plants, as we have seen, were taller and considerably heavier than the plants of the other two lots, and they produced a greater number of capsules than did even the Westerham-crossed plants; and this may be attributed to the latter having grown more crowded and being in consequence less branched. Therefore the average weight of an equal number of capsules from each lot of plants seems to be the fairest standard of comparison, as their weights will have been determined chiefly by the number of the included seeds. As the intercrossed plants were taller and heavier than the plants of the other two lots, it might have been expected that they would have produced the finest or heaviest capsules; but this was very far from being the case.
The ten tallest Westerham-crossed plants produced 111 ripe and unripe capsules, weighing 121.2 grains. Therefore 100 of such capsules would have weighed 109.18 grains.