5, and the fifteen
self-fertilised 33.55 inches in height; or as 100 to 97. So that the
excess of height of the crossed plants is quite insignificant. In
productiveness, however, the difference was much more plainly marked.
All the capsules were gathered from both lots of plants (except from the
crowded and unproductive ones in Pot 5), and at the close of the season
the few remaining flowers were added in. The fourteen crossed plants
produced 381, whilst the fourteen self-fertilised plants produced only
293 capsules and flowers; or as 100 to 77.
Dianthus caryophyllus.
The common carnation is strongly proterandrous, and therefore depends to
a large extent upon insects for fertilisation. I have seen only
humble-bees visiting the flowers, but I dare say other insects likewise
do so. It is notorious that if pure seed is desired, the greatest care
is necessary to prevent the varieties which grow in the same garden from
intercrossing. (4/10. 'Gardeners' Chronicle' 1847 page 268.) The pollen
is generally shed and lost before the two stigmas in the same flower
diverge and are ready to be fertilised. I was therefore often forced to
use for self-fertilisation pollen from the same plant instead of from
the same flower. But on two occasions, when I attended to this point, I
was not able to detect any marked difference in the number of seeds
produced by these two forms of self-fertilisation.
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