Four-leaf clover


The four-leaf clover is a very rare variation of the common three-leaf clover. According to traditional sayings, such clovers bring good luck, though it is not clear when or how this idea began. The earliest mention of "Fower-leafed or purple grasse" is from 1640 and simply says that it was kept in gardens because it was "good for the purples in children or others". A description from 1869 says that four-leaf clovers were "gathered at night-time during the full moon by sorceresses, who mixed it with vervain and other ingredients, while young girls in search of a token of perfect happiness made quest of the plant by day". The first reference to luck might be from an 11-year-old girl, who wrote in an 1877 letter to St. Nicholas Magazine, "Did the fairies ever whisper in your ear, that a four-leaf clover brought good luck to the finder?"

Occurrence

It is claimed that there are approximately 10,000 three-leaf clovers for every four-leaf clover. However, an actual survey of over 5 million clovers found the real frequency to be closer to 5,000 to 1, twice the said probability. Even so, this probability has not deterred collectors who have reached records as high as 160,000 four-leaf clovers in a lifetime. The world record for number collected in one hour is 166, set by American Katie Borka on June 23, 2018.
Clovers can have more than four leaves. Five-leaf clovers are less commonly found naturally than four-leaf clovers; however, they, too, have been successfully cultivated. Some four-leaf clover collectors, particularly in Ireland, regard the five-leaf clover, known as a rose clover, as a particular prize. The most leaves ever found on a single clover stem is 56 and was discovered by Shigeo Obara of Hanamaki City, Iwate, Japan, on 10 May 2009.

Cause

It is debated whether the fourth leaf is caused genetically or environmentally. Its relative rarity suggests a possible recessive gene appearing at a low frequency. Alternatively, four-leaf clovers could be caused by somatic mutation or a developmental error of environmental causes. They could also be caused by the interaction of several genes that happen to segregate in the individual plant. It is possible all four explanations could apply to individual cases. This means that multiple four-leaf clovers could be found in the same cloverplant.
Researchers from the University of Georgia have reported finding the gene that turns ordinary three-leaf clovers into the coveted four-leaf types. Masked by the three-leaf gene and strongly influenced by environmental condition, molecular markers now make it possible to detect the presence of the gene for four-leaves and for breeders to work with it. The results of the study, which also located two other leaf traits in the white-clover genome, were reported in the July/August 2010 edition of Crop Science, published by the Crop Science Society of America.
The other leaf traits, the red fleck mark and red midrib, a herringbone pattern that streaks down the center of each leaflet in a bold red color, were mapped to nearby locations, resolving a century-old question as to whether these leaf traits were controlled by one gene or two separate genes.
White clover has many genes that affect leaf color and shape, and the three in the study were very rare. These traits can be quite attractive, particularly if combined with others, and can turn clover into an ornamental plant for use in flower beds.
There are reports of farms in the US which specialize in four-leaf clovers, producing as many as 10,000 a day by introducing a genetically engineered ingredient to the plants to encourage the aberration.

Multi-leaved cultivars

There are some cultivars of white clover which regularly produce more than three leaflets, including purple-leaved T. repens "Purpurascens Quadrifolium" and green-leaved T. repens "Quadrifolium". Some clovers have more spade shape leaves, rather than the usual rounded ones. This may be another plant, or another genetic mutation. Some genetic mutations in clovers include spade-like shaped leaves or a dotted rusty colour on the leaves.
Trifolium repens "Good Luck" is a cultivar which has three, four, or five green, dark-centered leaflets per leaf.

Other species

Other plants may be mistaken for, or misleadingly sold as, "four-leaf clovers"; for example, Oxalis tetraphylla is a species of wood sorrel with leaves resembling a four-leaf clover. Other species that have been sold as "four-leaf clovers" include Marsilea quadrifolia.

Symbolic usage

Some folk traditions assign a different attribute to each leaf of a clover. The first leaf represents hope, the second stands for faith, the third is for love and the fourth leaf brings luck to the finder. A fifth leaf represents money. Some reports claim six to be fame and seven to be longevity, though the notions' origination is unknown.
Others say that four-leaf clovers granted the power to see fairies, or that they are related to St. Patrick's use of the shamrock to explain the Christian doctrine of the Holy Trinity to the Irish.