Parts of a Flower
typical flower grows on a receptacle, or
torus, an enlarged part of the flower
stalk. The flower consists of four whorls,
or sets, of parts. The outermost whorl is the calyx.
Within the calyx is the corolla. The
calyx and corolla together form the perianth.
The stamens, or male reproductive
organs, lie within the corolla. The pistils,
or female parts of the flower, make up the
innermost whorl of parts.
Calyx is usually made up of small,
green, leaflike sepals. These sepals
protect the delicate inner parts of the flower
bud. When the bud matures, the sepals usually
spread apart widely, and may drop off. To prevent
such insects as ants and beetles from climbing
into the flower from below, the sepals may bend
backward or bear special bristly structures.
The Corolla usually
consists of a group of colorful petals.
The bright colors of the corolla attract insects
and birds that pollinate the flower. Some
flowers, such as the anemones, have no corolla.
Their sepals have become petal-like in color and
function. In many plants of the lily family, the
sepals and petals are almost identical in size,
shape, and color. Such sepals and petals together
are called tepals. Lizard's-tail flowers
have neither calyx nor corolla, and botanists
call them naked flowers.
The petals of a flower may unite to form a
structure resembling a tube, saucer, pouch, or
other object. In the morning-glory,
the corolla looks like a bell; in the moccasin
flower, like a slipper; in the canary-bird vine,
like a tiny flying canary; and in the sacred
datura, like a long trumpet. The doubled
flowers of our gardens, such as carnations and
cabbage roses, may have hundreds of petals.
The Stamens may vary
in number from one to more than a thousand. They
are usually separate from each other, but in some
flowers they grow together to form a ring or cup
and in others, such as lobelias, lupines, and
mallows, they join to form a tube.
In most plants, each stamen has a long, narrow
filament, or stalk. Most filaments are
like threads, but some are flat and look like
paper. Others may have winged or toothlike edges.
On top of the filament is an enlargement called
the anther. The anther usually consists
of four baglike structures called pollen sacs
or micro-sporangia. Dustlike pollen is
produced in the sacs. Stamens are called staminodes
if they lack anthers or if the anthers fail to
The Pistils may vary
in number from one to many. In some flowers,
several separate pistils may join together to
form a single compound pistil. Each
pistil normally consists of three parts: the stigma,
the style, and the ovary.
The stigma, at the top, may be large and
feathery or small and hard to see. When the
stigma is "ripe," its sticky upper
surface catches and holds any pollen grains that
fall on it. Beneath the stigma, the long, slender
style leads to a round or long chamber called the
ovary. Sometimes the pistil has no style, and the
stigma rests directly on top of the ovary. The ovules
(egg cells) that develop into seeds, grow inside
World Book Encyclopedia.
Chicago: World Book-Childcraft International,
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