CROSSED AND SELF-FERTILISED PLANTS OF THE SIXTH GENERATION.
These were raised in the usual manner, with the following result. I
should state that there were originally eight plants on each side; but
as two of the self-fertilised became extremely unhealthy and never grew
to near their full height, these as well as their opponents have been
struck out of the list. If they had been retained, they would have made
the average height of the crossed plants unfairly greater than that of
the self-fertilised. I have acted in the same manner in a few other
instances, when one of a pair plainly became very unhealthy.
TABLE 2/7. Ipomoea purpurea (Sixth Generation).
Heights of Plants in inches:
Column 1: Number (Name) of Pot.
Column 2: Crossed Plants.
Column 3: Self-fertilised Plants.
Pot 1 : 93 : 50 1/2.
Pot 1 : 91 : 65.
Pot 2 : 79 : 50.
Pot 2 : 86 1/2 : 87.
Pot 2 : 88 : 62.
Pot 3 : 87 1/2 : 64 1/2.
Total : 525 : 379.
The average height of the six crossed plants is here 87.5, and of the
six self-fertilised plants 63.16, or as 100 to 72. This large difference
was chiefly due to most of the plants, especially the self-fertilised
ones, having become unhealthy towards the close of their growth, and
they were severely attacked by aphides. From this cause nothing can be
inferred with respect to their relative fertility.
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