5
seeds; so that the seeds in the naturally intercrossed capsules to those
in the self-fertilised capsules were as 100 to 16. The interesting point
in this case is that these plants, which were unnaturally treated by
being grown in pots in a hothouse, under another hemisphere, with a
complete reversal of the seasons, were thus rendered slightly
self-fertile, whereas they seem always to be completely self-sterile in
their native home.
Senecio cruentus (greenhouse varieties, commonly called Cinerarias,
probably derived from several fruticose or herbaceous species much
intercrossed (9/10. I am much obliged to Mr. Moore and to Mr. Thiselton
Dyer for giving me information with respect to the varieties on which I
experimented. Mr. Moore believes that Senecio cruentas, tussilaginis,
and perhaps heritieri, maderensis and populifolius have all been more or
less blended together in our Cinerarias.))
Two purple-flowered varieties were placed under a net in the greenhouse,
and four corymbs on each were repeatedly brushed with flowers from the
other plant, so that their stigmas were well covered with each other's
pollen. Two of the eight corymbs thus treated produced very few seeds,
but the other six produced on an average 41.3 seeds per corymb, and
these germinated well. The stigmas on four other corymbs on both plants
were well smeared with pollen from the flowers on their own corymbs;
these eight corymbs produced altogether ten extremely poor seeds, which
proved incapable of germinating.
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