7 grains. Therefore the sterility of the
present species, when insects are excluded, is not due to the impotence
of pollen on the stigma of the same flower. Both lots of seeds and
seedlings were treated in exactly the same manner as in Table 3/23,
excepting that after the pairs of germinating seeds had been planted on
the opposite sides of eight pots, all the remaining seeds were thickly
sown on the opposite sides of Pots 9 and 10 in Table 3/24. The young
plants during the following spring were turned out of their pots,
without being disturbed, and planted in the open ground in two rows, not
very close together, so that they were subjected to only moderately
severe competition with one another. Very differently to what occurred
in the first experiment, when the plants were subjected to somewhat
severe mutual competition, an equal number on each side either died or
did not produce flower-stems. The tallest flower-stems on the surviving
plants were measured, as shown in Table 3/24.
TABLE 3/24. Digitalis purpurea.
The tallest Flower-stem on each Plant measured in inches: 0 signifies
that the Plant died, or did not produce a Flower-stem.
Column 1: Number (Name) of Pot.
Column 2: Plants raised from a Cross between different Flowers on the
same Plant.
Column 3: Plants raised from Flowers fertilised with their own Pollen.
Pot 1 : 49 4/8 : 45 5/8.
Pot 1 : 46 7/8 : 52.
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