The extrusion of the pollen is also aided by insects,
which rub against the little bristles that project from the anthers. The
pollen thus pushed out is carried by insects to the older flowers, in
which the stigma of the now freely projecting pistil is open and ready
to be fertilised. I proved the importance of the gaily-coloured corolla,
by cutting off the large flowers of Lobelia erinus; and these flowers
were neglected by the hive-bees which were incessantly visiting the
other flowers.
A capsule was obtained by crossing a flower of L. ramosa with pollen
from another plant, and two other capsules from artificially
self-fertilised flowers. The contained seeds were sown on the opposite
sides of four pots. Some of the crossed seedlings which came up before
the others had to be pulled up and thrown away. Whilst the plants were
very small there was not much difference in height between the two lots;
but in Pot 3 the self-fertilised were for a time the tallest. When in
full flower the tallest plant on each side of each pot was measured, and
the result is shown in Table 5/68. In all four pots a crossed plant
flowered before any one of its opponents.
TABLE 5/68. Lobelia ramosa (First Generation).
Heights of plants measured in inches.
Column 1: Number (Name) of Pot.
Column 2: Tallest Crossed Plant in each Pot.
Column 3: Tallest Self-fertilised Plant in each Pot.
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