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Darwin, Charles, 1809-1882

"Effects of Cross and Self Fertilisation in the Vegetable Kingdom"

), and Tritoma; the two
former plants being endemic, and the two latter exotic. As wasps are so
fond of sugar and of any sweet fluid, and as they do not disdain the
minute drops on the glands of Prunus laurocerasus, it is a strange fact
that they do not suck the nectar of many open flowers, which they could
do without the aid of a proboscis. Hive-bees visit the flowers of the
Symphoricarpus and Tritoma, and this makes it all the stranger that they
do not visit the flowers of the Epipactis, or, as far as I have seen,
those of the Scrophularia aquatica; although they do visit the flowers
of Scrophularia nodosa, at least in North America. (11/11. 'Silliman's
American Journal of Science' August 1871.)
The extraordinary industry of bees and the number of flowers which they
visit within a short time, so that each flower is visited repeatedly,
must greatly increase the chance of each receiving pollen from a
distinct plant. When the nectar is in any way hidden, bees cannot tell
without inserting their proboscides whether it has lately been exhausted
by other bees, and this, as remarked in a former chapter, forces them to
visit many more flowers than they otherwise would. But they endeavour to
lose as little time as they can; thus in flowers having several
nectaries, if they find one dry they do not try the others, but as I
have often observed, pass on to another flower.


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