In 1863 a protected long-styled plant produced only five
poor capsules; two mid-styled plants produced together the same number; and two
short-styled plants only a single one. These capsules contained very few seeds;
yet the plants were fully productive when artificially fertilised under the net.
In a state of nature the flowers are incessantly visited for their nectar by
hive- and other bees, various Diptera and Lepidoptera. (4/3. H. Muller gives a
list of the species 'Die Befruchtung der Blumen' page 196. It appears that one
bee, the Cilissa melanura, almost confines its visits to this plant.) The nectar
is secreted all round the base of the ovarium; but a passage is formed along the
upper and inner side of the flower by the lateral deflection (not represented in
the diagram) of the basal portions of the filaments; so that insects invariably
alight on the projecting stamens and pistil, and insert their proboscides along
the upper and inner margin of the corolla. We can now see why the ends of the
stamens with their anthers, and the ends of the pistils with their stigmas, are
a little upturned, so that they may be brushed by the lower hairy surfaces of
the insects' bodies. The shortest stamens which lie enclosed within the calyx of
the long- and mid-styled forms can be touched only by the proboscis and narrow
chin of a bee; hence they have their ends more upturned, and they are graduated
in length, so as to fall into a narrow file, sure to be raked by the thin
intruding proboscis.
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