There was also pollen on the chin, and,
it may be presumed, on the proboscis, but this was difficult to observe. I had,
however, independent proof that pollen is carried on the proboscis; for a small
branch of a protected short-styled plant (which produced spontaneously only two
capsules) was accidentally left during several days pressing against the net,
and bees were seen inserting their proboscides through the meshes, and in
consequence numerous capsules were formed on this one small branch. From these
several facts it follows that insects will generally carry the pollen of each
form from the stamens to the pistil of corresponding length; and we shall
presently see the importance of this adaptation. It must not, however, be
supposed that the bees do not get more or less dusted all over with the several
kinds of pollen; for this could be seen to occur with the green pollen from the
longest stamens. Moreover a case will presently be given of a long-styled plant
producing an abundance of capsules, though growing quite by itself, and the
flowers must have been fertilised by their own kinds of pollen; but these
capsules contained a very poor average of seed. Hence insects, and chiefly bees,
act both as general carriers of pollen, and as special carriers of the right
sort.
Wirtgen remarks on the variability of this plant in the branching of the stem,
in the length of the bracteae, size of the petals, and in several other
characters.
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