Faramea [sp.?] (Rubiaceae).
(FIGURE 3.9. Faramea [sp.?]
Left: Short-styled form.
Right: Long-styled form.
Outlines of flowers from dried specimens. Pollen-grains magnified 180 times, by
Fritz Muller.)
Fritz Muller has fully described the two forms of this remarkable plant, an
inhabitant of South Brazil. (3/24. 'Botanische Zeitung' September 10, 1869 page
606.) In the long-styled form the pistil projects above the corolla, and is
almost exactly twice as long as that of the short-styled, which is included
within the tube. The former is divided into two rather short and broad stigmas,
whilst the short-styled pistil is divided into two long, thin, sometimes much
curled stigmas. The stamens of each form correspond in height or length with the
pistils of the other form. The anthers of the short-styled form are a little
larger than those of the long-styled; and their pollen-grains are to those of
the other form as 100 to 67 in diameter. But the pollen-grains of the two forms
differ in a much more remarkable manner, of which no other instance is known;
those from the short-styled flowers being covered with sharp points; the smaller
ones from the long-styled being quite smooth. Fritz Muller remarks that this
difference between the pollen-grains of the two forms is evidently of service to
the plant; for the grains from the projecting stamens of the short-styled form,
if smooth, would have been liable to be blown away by the wind, and would thus
have been lost; but the little points on their surfaces cause them to cohere,
and at the same time favour their adhesion to the hairy bodies of insects, which
merely brush against the anthers of these stamens whilst visiting the flowers.
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