CROSSED AND SELF-FERTILISED PLANTS OF THE FIFTH GENERATION.
These were raised in the same manner as before, and when measured gave the following results:—
TABLE 2/6. Ipomoea purpurea (Fifth Generation).
Heights of Plants in inches:
Column 1: Number (Name) of Pot.
Column 2: Crossed Plants.
Column 3: Self-fertilised Plants.
Pot 1 : 96 : 73. Pot 1 : 86 : 78. Pot 1 : 69 : 29.
Pot 2 : 84 : 51. Pot 2 : 84 : 84. Pot 2 : 76 1/4 : 59.
Total : 495.25 : 374.00.
The average height of the six crossed plants is 82.54 inches, and that of the six self-fertilised plants 62.33 inches, or as 100 to 75. Every crossed plant exceeded its antagonist in height. In Pot 1 the middle plant on the crossed side was slightly injured whilst young by a blow, and was for a time beaten by its opponent, but ultimately recovered the usual superiority. The crossed plants produced spontaneously a vast number more capsules than did the self-fertilised plants; and the capsules of the former contained on an average 3.37 seeds, whilst those of the latter contained only 3.0 per capsule, or as 100 to 89. But looking only to the artificially fertilised capsules, those on the crossed plants again crossed contained on an average 4.46 seeds, whilst those on the self-fertilised plants again self-fertilised contained 4.77 seeds; so that the self-fertilised capsules were the more fertile of the two, and of this unusual fact I can offer no explanation.