Asa Gray
'Manual of Botany of the United States' 1856 page 540.) The anthers shed their
pollen on the stigma; at least in one instance this was clearly the case, and by
tearing open the anthers under water the grains were easily detached. Towards
the apex of the anther the grains are arranged in a single row and lower down in
two or three rows, so that they could be counted; and there were about 35 in
each cell, or 70 in the whole anther; and this is an astonishingly small number
for an anemophilous plant. The grains have very delicate coats, are spherical
and about 5/7000 of an inch (.0181 millimetres), whilst those of the perfect
flowers are about 7/7000 of an inch (.0254 millimetres) in diameter.
M. Duval-Jouve states that the panicles very rarely protrude from their sheaths,
but that when this does happen the flowers expand and exhibit well-developed
ovaries and stigmas, together with full-sized anthers containing apparently
sound pollen; nevertheless such flowers are invariably quite sterile. Schreiber
had previously observed that if a panicle is only half protruded, this half is
sterile, whilst the still included half is fertile. Some plants which grew in a
large tub of water in my greenhouse behaved on one occasion in a very different
manner. They protruded two very large much-branched panicles; but the florets
never opened, though these included fully developed stigmas, and stamens
supported on long filaments with large anthers that dehisced properly.
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