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The Clovers
Nature Bulletin No. 304-A April 27, 1968
Forest Preserve District of Cook County
Richard B. Ogilvie, President
Roland F. Eisenbeis, Supt. of Conservation
THE CLOVERS
Modern agriculture and the livestock industry depend upon two plant
families: the grasses, which include the cereals; and the legumes.
Alfalfa, known to the Medes and Persions, had been widely raised in
the Roman empire, and other legumes -- such as peas, beans, lentils,
peanuts and soybeans -- had been grown for thousands of years in
various parts of the world but, until about 1500 A. D., the grasses had
furnished most of the food for man and his animals. Then Red Clover, a
legume native in Europe, began to be cultivated in Italy and Spain as a
forage crop for livestock. From there it was introduced into Holland,
where it was called 'Klafver", and thence to England. In 1759, farmers
in Pennsylvania were sowing clover seed in their fields "to make the
crop stronger".
A balanced ration for horses, cattle, sheep, swine and poultry must
include proteins, minerals, and starches which they get from cereal
grains, Legumes contain more protein than pasture grasses in their
leaves and stems, even when mature or cut for hay, Legumes also
contain large amounts of calcium, some phosphorus and other minerals,
and are the most convenient sources of vitamins A and D. Further,
legumes are unique in having a partnership with certain bacteria which
grow in little gall-like knobs, called tubercles, upon the roots. These
bacteria have the peculiar power of taking nitrogen from the air in the
soil and "fixing" it so that it is left available as food for other plants.
Thus, legumes enrich the soil. Clovers, especially, are regularly used in
systems of crop rotation and pasture management.
The true clovers have leaves divided into three leaflets -- occasionally
one may have 4 or more -- and the blossoms are dense heads of as many
as 200 individual flowers in the case of red clover and white clover, or
as few as 5 on hop clover. These flowers are unique in that they remain
on the head, brown and withered, but each has its parts arranged in the
butterfly-like pattern peculiar to all legumes and each seed is encased in
a tiny pod. Only nine species are of major importance to agriculture in
the United States. Six of these -- Crimson, Strawberry, Persian, Small
Hop (said to be the ancestor of the shamrock), Large Hop, and Sub
Clover -- are principally adapted to certain regions for special purposes
such as grazing.
In our northern states, Red Clover, a biennial, is the "big shot" for
pastures, hay, and crop rotations. There are a large number of improved
varieties and local strains, including a tall coarse perennial variety
called "Mammoth" Clover, used principally as a soil improver. Red
Clover, like many clovers, will not bear seeds unless it is fertilized by
insects carrying pollen on their bodies from one blossom to another. It
depends upon bumblebees which, with the exception of some
butterflies, are the only insects with a tongue long enough to reach the
nectar at the bottom of the flowers; and upon honeybees which come to
get pollen for "bee bread"'.
White Clover, or Dutch Clover, has become native over most of North
America in pastures and lawns. Its pure white blossoms are rich in
nectar and a principal source of honey. The common kinds are low
spreading plants but a tall variety, La dino Clover, has been widely used
for pastures in recent years. Alsike Clover named for a place in Sweden,
is a perennial from one to two feet tall that is more hardy than red clove
r and will grow in wet soils. Its blossoms turn from white to rose color.
It is an important plant for pastures and for honey.
Red Clover is the state flower of Vermont, the shamrock is Ireland's
emblem, and the four-leafed clover is the emblem of good luck.
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