meters long and several decimeters wide. Spines
generally occur along the whole margin of the leaf, though in a few
forms, especially in cultivated varieties, they may be present only
at the tip or may be wanting entirely. The marginal spines usually
curve forward and vary in size from small, hardly perceptible forms,
to large sharp conical structures. At times they are set very close
together; again they may be several centimeters apart. Those on
the midrib most often curve backwards and may vary the same as the
marginal spines. Generally the spines are green in color, though in
some species they are pale-green, red, black or white.

Some forms seem to creep along the ground, while others, low and bushy
and standing close together, form, with their numerous supporting
prop roots, an almost impenetrable jungle. The high tree forms are
very striking because of their peculiarly shaped crowns.

The first roots which the pandans develop soon disappear and their
place is taken by others. Starting high above the ground, these grow
at an angle from the stem and generally reach the soil. They serve
the twofold purpose of supporting the stem and of supplying it with
sufficient air. If, by accident, the underground roots die off,
the plant relies entirely on these air and prop roots for support
and food. The strong prop roots are generally of the same diameter
throughout, though sometimes they thicken at the ends. Normally they
never branch above the ground, but after reaching the soil very often
divide. The tip of the roots is protected by a cap, while a layer of
cork tissue prevents the drying out of the root body.

The pandan has two kinds of flowers, male and female. The male flowers
are arranged in the form of a spike protected by a modified leaf
called the bract. They are white in color, crowded together on the
spike and consist of stamens which hold the pollen. The flowers do
not have the showy colored bracts which forms so prominent a feature
in those of many other plants. The female flowers consist only of the
necessary parts. As the pollen occurs in enormous quantities and as
the plants generally grow in groups, it is very probable that some
flowers are pollinated by the wind. The fact that many pandans have
very fragrant blossoms makes it almost certain that in the majority of
cases insect pollination takes place. In a few forms that have a very
disagreeable odor, pollination is effected by night flying insects.

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