s and sedges, and the plantains--the flowers are
more or less raised up on the haulm. An exception must be made of some
water-plants--_e.g._, the Potamogetons, where the flower-stalk is but
slightly raised above the surface.

Wind-fertilised plants have many characteristics which favour the
dispersal of the pollen. The grasses have long pendent stamens, and
versatile anthers, from which the pollen is easily shaken out by the
wind. There are, of course, exceptions to these generalisations. Such
plants as Hippuris and Salicornia have no particular adaptations: the
filaments are short, and the plants themselves are not of sufficient
height to be able to scatter forth their pollen efficiently by the mere
bending of their stems. The need for exposure to the wind is shown in
another way--namely, by the habit of the Cupuliferae (oak, hazel, etc.),
of flowering before the leaves appear; this not only favours the start of
the pollen on its flight, but is probably still more useful in increasing
its chance of reaching the stigma.

If the pollen is exposed to the wind it will be liable to be wetted and
injured. Catkins--such as those of the walnut or hazel--give some
protection to the pollen, since the stamens are covered in by tile-like
scales; but where--as in the grasses and plantains--the anthers hang far
out of the flowers, the pollen is easily injured. Some of the cereals
protect themselves against injury by means of a remarkably rapid growth
of the filaments; thus the anthers remain hidden within the flowers until
the last moment, and, under the influence of a warm sunny morning,
rapidly protrude themselves. If the scales of the flower are
artificially separated, the growth can be produced by warmth and
moisture; Askenasy describes a trick of country children, who put ears of
rye in their mouths and thus produce a miraculous growth of stamens. The
growth or rapid turgescence takes place, according to the same writer, at
the pace of one millimetre in three minutes.

The explosive male flowers of the nettle have a somewhat similar meaning.
The young stamen is bent so that the upper end of the anther touches the
base of the filament. On the inner concave side of the stamen are large
cells, whose turgescence tends to unfold the filament: I do not know by
what means the unfolding is prevented, but whatever the cause may be, it
is at last overcome and the stamen uncurls with a jerk, and scatters
forth the pollen. Her