After casually
observing that some of these plants were self-sterile, two plants taken
by hazard were protected under separate nets. One of these soon became
covered with spontaneously self-fertilised capsules, as numerous as
those on the surrounding unprotected plants; so that it was evidently
quite self-fertile. The other plant was partially self-sterile,
producing very few capsules, many of which were of small size. When,
however, this plant had grown tall, the uppermost branches became
pressed against the net and grew crooked, and in this position the bees
were able to suck the flowers through the meshes, and brought pollen to
them from the neighbouring plants. These branches then became loaded
with capsules; the other and lower branches remaining almost bare. The
sexual constitution of this species is therefore similar to that of
Reseda odorata.
CONCLUDING REMARKS ON SELF-STERILE PLANTS.
In order to favour as far as possible the self-fertilisation of some of
the foregoing plants, all the flowers on Reseda odorata and some of
those on the Abutilon were fertilised with pollen from other flowers on
the same plant, instead of with their own pollen, and in the case of the
Senecio with pollen from other flowers on the same corymb; but this made
no difference in the result. Fritz Muller tried both kinds of
self-fertilisation in the case of Bignonia, Tabernaemontana and
Abutilon, likewise with no difference in the result.
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