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THE PLANT

Crosses Hybrids And Cross-pollination
How A Plant Feeds From The Air
Plant Seeding
Pollination
Propagation By Buds
Selecting Seed Corn
The Flower And The Seed
The Rotation Of Crops
The Sap Current
Weeds

More from THE PLANT

Agriculture For Beginners

115
174
Barley
Bee Culture
Birds
Buckwheat
Budding
Cattle
Corn
Cotton
Draining The Soil
Farm Poultry
Farm Tools And Machines
Farming On Dry Lands
Flower Gardening



The Flower And The Seed








Some people think that the flowers by the wayside are for the purpose of
beautifying the world and increasing man's enjoyment. Do you think this
is true? Undoubtedly a flower is beautiful, and to be beautiful is one
of the uses of many flowers; but it is not the chief use of a flower.

You know that when peach or apple blossoms are nipped by the spring
frost the fruit crop is in danger. The fruit of the plant bears the
seed, and the flower produces the fruit. That is its chief duty.



Do you know any plant that produces seed without flowers? Some one
answers, "The corn, the elm, and the maple all produce seed, but have no
flower." No, that is not correct. If you look closely you will find in
the spring very small flowers on the elm and on the maple, while the ear
and the tassel are really the blossoms of the corn plant. Every plant
that produces seed has flowers, although they may sometimes seem very
curious flowers.



Let us see what a flower really is. Take, for example, a buttercup,
cotton, tobacco, or plum blossom (see Figs. 31 and 32). You will find on
the outside a row of green leaves inclosing the flower when it is still
a bud. These leaves are the _sepals_. Next on the inside is a row of
colored leaves, or _petals_. Arranged inside of the petals are some
threadlike parts, each with a knob on the end. These are the _stamens_.
Examine one stamen closely (Fig. 33). On the knob at its tip you should
find, if the flower is fully open, some fine grains, or powder. In the
lily this powder is so abundant that in smelling the flower you often
brush a quantity of it off on your nose. This substance is called
_pollen_, and the knob on the end of the stamen, on which the pollen is
borne, is the _anther_.



The pollen is of very great importance to the flower. Without it there
could be no seeds. The stamens as pollen-bearers, then, are very
important. But there is another part to each flower that is of equal
value. This part you will find in the center of the flower, inside the
circle of stamens. It is called the _pistil_ (Fig. 32). The swollen tip
of the pistil is the _stigma_. The swollen base of the pistil forms the
_ovary_. If you carefully cut open this ovary you will find in it
very small immature seeds.


_a_, anther; _f_, filament]

Some plants bear all these parts in the same flower; that is, each
blossom has stamens, pistil, petals, and sepals. The pear blossom and
the tomato blossom represent such flowers. Other plants bear their
stamens and pistils in separate blossoms. Stamens and pistils may even
occur in separate plants, and some blossoms have no sepals or petals at
all. Look at the corn plant. Here the tassel is a cluster of many
flowers, each of which bears only stamens. The ear is likewise a cluster
of many flowers, each of which bears only a pistil. The dust that you
see falling from the tassel is the pollen, and the long silky threads of
the ear are the stigmas.



Now no plant can bear seeds unless the pollen of the stamen falls on the
stigma. Corn cannot therefore form seed unless the dust of the tassel
falls upon the silk. Did you ever notice how poorly the cob is filled on
a single cornstalk standing alone in a field? Do you see why? It is
because when a plant stands alone the wind blows the pollen away from
the tassel, and little or none is received on the stigmas below.



In the corn plant the stamens and pistils are separate; that is, they do
not occur on the same flower, although they are on the same plant. This
is also true of the cucumber (see Fig. 35). In many plants, however,
such as the hemp, hop, sassafras, willow, and others, the staminate
parts are on one plant and the pistillate parts are on another. This is
also true in several other cultivated plants. For example, in some
strawberries the stamens are absent or useless; that is, they bear no
good pollen. In such cases the grower must see to it that near by are
strawberry plants that bear stamens, in order that those plants which do
not bear pollen may become _pollinated_; that is, may have pollen
carried to them. After the stigma has been supplied with pollen, a
single pollen grain sends a threadlike sprout down through the stigma
into the ovary. This process, if successfully completed, is called
_fertilization_.


=EXERCISE=

Examine several flowers and identify the parts named in the last
section. Try in the proper season to find the pollen on the maple,
willow, alder, and pine, and on wheat, cotton, and the
morning-glory.

How fast does the ovary of the apple blossom enlarge? Measure one
and watch it closely from day to day. Can you find any plants that
have their stamens and ovaries on separate individuals?





Next: Pollination

Previous: The Sap Current



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