Flower And Fruit 179

A fruit is the body produced by the development
of the ovary and surrounding parts as a result of
fertilisation. The ovules become the seeds and the
wall of the ovary becomes the wall of the fruit, which
may remain succulent or become dry and hard. The
great functions of the fruit are to protect the seed
and provide for its distribution.

Fruits may be simple, aggregate or composite,
simple fruits being derived from a single carpel or as a
number of united carpels, aggregate fruits from a
number of free carpels, and composite fruits, not from
a single flower but from an inflorescence. Simple
fruits may be either dry or succulent and dry simple
fruits may be either dehiscent or indehiscent, i.e.. they
may or may not open to let out their seeds.

The achene (Fig. 115) is the type of the dry
indehiscent form of simple fruits. It is formed from
a one-seeded superior ovary derived from a single
carpel, the pericarp (ovary wall) and testa afe free
from each other, and both are ruptured by the escaping
embryo. This is well seen in the dock and sorrel, and
in the individual members of the aggregate fruits of
the buttercup and clematis. The following fruits are
similar to achenes:-

1. The cypsela is the characteristic fruit of the
daisy family, and differs from the true achene in being
formed from an inferior ovary derived from two
united carpels. Its origin rather than its form con-
stitutes the difference.

2. The caryopsis is well seen in the wheat and maize
grains and the fruits of all other grasses. It differs
from the achene in having the testa and pericarp (i.e.,
the seed coat and seed case or ovary wall) fused
together.

3. The samara is a winged achene well seen in the
ash, elm, and ake-ake (Dodonoea).