Read about Clover in the Standard Cyclopedia of Horticulture 

Clover. Species of Trifolium (Leguminosae), particularly those that are useful in agriculture. The word is also applied to species of related genera, as Medicago. The sweet clover is Melilotus. Bush and Japan clover are Lespedezas. Prairie clover is a Petalostemon.

About 300 species of Trifolium have been described. These are widely dispersed in temperate climates. The flowers are papilionaceous but small, and are disposed in dense heads or spikes. The leaves are digitately or palmately 3-foliolate. The common European red clover is T. pratense, Linn., now thoroughly naturalized in North America, but supposed not to be native here. It is valuable both for stock feed (as pasturage and hay), and also as a green manure. As a manure crop, to be plowed under, it is particularly useful because of its deep root-system and its power (in common with other leguminous plants) of fixing the nitrogen of the air by means of its roots. Fig. 1001 illustrates the root system. Fig. 1002 shows the root of a fifteen months old plant that grew in hard clay soil. It is 22 inches long, and some of the root was left in the ground. The mammoth red clover (D. medium, Linn.) is perhaps an offshoot of T. pratense. It is usually a larger plant, with zigzag stem, entire and spotted leaflets, and longer- stalked head. White clover, or shamrock, is T. repens, Linn., introduced from Europe, and supposed to be native to North America as well. Alsike clover, T. hybridum, Linn., is of Old World nativity. The crimson or scarlet clover (T. incarnatum, Linn.), Fig. 1003, an annual from southern Europe, is now much grown as a catch- or cover crop in orchards. See Cover-crops. It is also highly ornamental, and is worthy the attention of the florist. For agricultural discussion of the clovers, see Vol. II, Cyclo. Amer. Agric. L. H. B. Cloves are the dried flower- buds (Fig. 1004) of a handsome tree of the myrtle family Jambosa Caryopliyllus or Eugenia caryophyllata, better known as Caryophyllus aromaticus, a native of the Spice Islands, but now cultivated in the West Indies and elsewhere. See Eugenia. Caryophyllus, the ancient name of the clove, means "nut-leaf. The carnation, or "clove pink, "was named Dianthus Caryophyllus because of its clove- like odor, and it has become the type of the great order Caryophyllacea, which, however, is far removed botanically from the Myrtaceae. The word "gilliflower" is a corruption of caryophyllus, and, until Shakespeare's time and after, was applied to the carnation, but now-a-days it usually refers to certain cruciferous plants of the genera Cheiranthus and Matthiola.

The clove bark of pharmacy is secured from Dicypellium caryophyllum, of Brazil, one of the Lauraceae. The word clove is used among gardeners for a small secondary bulb employed for propagating, specially for the little bulb that forms in a scale-axil of a larger bulb.


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Clover
clover inflorescence
clover inflorescence
Plant Info
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Tribe: Trifolieae
Genus: Trifolium
L.

Species
See text

Template:Commons

Clover (Trifolium) is a genus of about 300 species of plants in the pea family Fabaceae. The genus has a cosmopolitan distribution; the highest diversity is found in the temperate Northern Hemisphere, but many species also occur in South America and Africa, including at high altitudes on mountains in the tropics.

They are small annual, biennial, or short-lived perennial herbaceous plants. The leaves are trifoliate (rarely 5- or 7-foliate), with stipules adnate to the leaf-stalk, and heads or dense spikes of small red, purple, white, or yellow flowers; the small, few-seeded pods are enclosed in the calyx.

Other closely related genera often called clovers include Melilotus (sweet clover) and Medicago (alfalfa or 'calvary clover'). The "shamrock" of popular iconography is sometimes considered to be young clover.

The scientific name derives from the Latin tres, "three", and folium, "leaf", so called from the characteristic form of the leaf, which has three leaflets (trifoliate); hence the popular name trefoil. Clovers are used as food plants by the larvae of some Lepidoptera species; see list of Lepidoptera which feed on Clovers.

Red clover (Trifolium pratense)
Selected species

Cultivation

 
White Clover flower-head and leaves

Several species are extensively cultivated as fodder-plants. The most widely cultivated clovers are White clover Trifolium repens and Red clover Trifolium pratense. Clover, either sown alone or in mixture with ryegrass, has for a long time formed a staple crop for soiling, for several reasons; it grows freely, shooting up again after repeated mowings; it produces an abundant crop; it is palatable to and nutritious for livestock; it grows in a great range of soils and climates; and it is appropriate either for pasturage or green composting.

In many areas, particularly on acidic soils, clover is short-lived due a combination of insect pests, diseases and nutrient balance; this is known as "clover-sickness". When crop rotations are managed so that clover does not recur at shorter intervals than eight years, it grows with much of its pristine vigour.

"Clover sickness" in more recent times may also be linked to pollinator decline; clovers are most efficiently pollinated by bumblebees, which have declined as a result of agricultural intensification. Honeybees can also pollinate clover, and beekeepers are often in heavy demand from farmers with clover pastures. Farmers enjoy the benefits of increased reseeding that occurs with increased bee activity, which means that future clover yields remain abundant. Beekeepers benefit from the clover bloom as clover is one of the main nectar sources for honeybees.

 
Red Clover flowers

T. repens, White or Dutch clover, is a perennial abundant in meadows and good pastures. The flowers are white or pinkish, becoming brown and deflexed as the corolla fades. T. hybridum, Alsike or Swedish clover, is a perennial which was introduced early in the 19th century and has now become naturalized in Britain. The flowers are white or rosy, and resemble those of the last species. T. medium, meadow or zigzag clover, a perennial with straggling flexuous stems and rose-purple flowers, is of little agricultural value.

 
White Clover flower

Other British species are: T. arvense, Hare's-foot trefoil; found in fields and dry pastures, a soft hairy plant with minute white or pale pink flowers and feathery sepals; T. fragiferum, Strawberry clover, with densely-flowered, globose, rose-purple heads and swollen calyxes; T. procumbens, Hop trefoil, on dry pastures and roadsides, the heads of pale yellow flowers suggesting miniature hops; and the somewhat similar T. minus, common in pastures and roadsides, with smaller heads and small yellow flowers turning dark brown. The last named is often called Shamrock.

Clovers are a valuable survival food, as they are high in protein, widespread, and abundant. They are not easy to digest raw, but this can be easily fixed by boiling for 5-10 minutes. Dried flowerheads and seedpods can also be ground up into a nutritious flour and mixed with other foods. Dried flowerheads can also be steeped in hot water for a healthy, tasty tea.

Symbolism and mythology

 
A four-leaf clover

Shamrock, the traditional Irish symbol coined by Saint Patrick for the Holy Trinity, is commonly associated with clover, though also sometimes with Oxalis species, which also have trifoliate leaves.

Clovers occasionally have leaves with four leaflets, instead of the usual three. These four-leaf clovers, like other rarities, are considered lucky.

A common idiom is "to be in clover", meaning to be living a carefree life of ease, comfort, or prosperity.

The cloverleaf interchange is named for the resemblance to the leaves of a (four-leafed) clover when viewed from the air.

References