Crossed and self-fertilised plants of the second generation.

Some flowers on the crossed plants of the last generation were again crossed with pollen from another crossed plant, and produced fine capsules.  The flowers on the self-fertilised plants of the last generation were allowed to fertilise themselves spontaneously under a net, and they produced some remarkably fine capsules.  The two lots of seeds thus produced germinated on sand, and eight pairs were planted on opposite sides of four pots.  These plants were measured to the tips of their leaves on the 20th of October of the same year, and the eight crossed plants averaged in height 8.4 inches, whilst the self-fertilised averaged 8.53 inches, so that the crossed were a little inferior in height, as 100 to 101.5.  By the 5th of June of the following year these plants had grown much bulkier, and had begun to form heads.  The crossed had now acquired a marked superiority in general appearance, and averaged 8.02 inches in height, whilst the self-fertilised averaged 7.31 inches; or as 100 to 91.  The plants were then turned out of their pots and planted undisturbed in the open ground.  By the 5th of August their heads were fully formed, but several had grown so crooked that their heights could hardly be measured with accuracy.  The crossed plants, however, were on the whole considerably taller than the self-fertilised.  In the following year they flowered; the crossed plants flowering before the self-fertilised in three of the pots, and at the same time in Pot 2.  The flower-stems were now measured, as shown in Table 4/29.

Table 3/29.  Brassica oleracea.

Measured in inches to tops of flower-stems:  0 signifies that a
Flower-stem was not formed.

Column 1:  Number (Name) of Pot.

Column 2:  Crossed Plants.

Column 3:  Self-fertilised Plants.

Pot 1 :  49 2/8 :  44. 
Pot 1 :  39 4/8 :  41.

Pot 2 :  37 4/8 :  38. 
Pot 2 :  33 4/8 :  35 4/8.

Pot 3 :  47 :  51 1/8. 
Pot 3 :  40 :  41 2/8. 
Pot 3 :  42 :  46 4/8.

Pot 4 :  43 6/8 :  20 2/8. 
Pot 4 :  37 2/8 :  33 3/8. 
Pot 4 :  0 :  0.

Total :  369.75 :  351.00.

The nine flower-stems on the crossed plants here average 41.08 inches, and the nine on the self-fertilised plants 39 inches in height, or as 100 to 95.  But this small difference, which, moreover, depended almost wholly on one of the self-fertilised plants being only 20 inches high, does not in the least show the vast superiority of the crossed over the self-fertilised plants.  Both lots, including the two plants in Pot 4, which did not flower, were now cut down close to the ground and weighed, but those in Pot 2 were excluded, for they had been accidentally injured by a fall during transplantation, and one was almost killed.  The eight crossed plants weighed 219 ounces, whilst the eight self-fertilised plants weighed only 82 ounces, or as 100 to 37; so that the superiority of the former over the latter in weight was great.