These three lots of plants were cut down close to the ground and weighed.  The twenty-one Westerham-crossed plants weighed 32 ounces; the twenty-two intercrossed plants, 34 ounces, and the twenty-one self-fertilised plants 7 1/4 ounces.  The following ratios are calculated for an equal number of plants of each kind.  But as the self-fertilised plants were just beginning to wither, their relative weight is here slightly too small; and as the Westerham-crossed were still growing vigorously, their relative weight with time allowed would no doubt have greatly increased.

The Westerham-crossed plants in weight to the self-fertilised as 100 to 22.

The Westerham-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.

We here see, judging by weight instead of as before by height, that the Westerham-crossed and the intercrossed have an immense advantage over the self-fertilised.  The Westerham-crossed are inferior to the 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 sown in three long parallel and adjoining rows in the open ground, so as to ascertain whether under these circumstances the results would be nearly the same as before.  Late in the autumn (November 13) the ten tallest plants were carefully selected out of each row, and their heights measured, with the following result:—­

Table 6/83.  Petunia violacea (plants growing in the open ground).

Heights of plants measured in inches.

Column 1:  Westerham-Crossed Plants (from self-fertilised Plants of the fourth generation crossed by a fresh stock).

Column 2:  intercrossed Plants (Plants of one and the same stock intercrossed for five generations).

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.