~ Jessica S. Herwick
Don’t be fooled this Saint Patrick’s Day by thevariety of plants whose leaf shape, coloring, or number of leaves imitate thoseof the elusive four leaf clover. Many of those lucky charms you mightcollect at your local bar, or wear during the neighborhood pub-crawl on SaintPatrick’s Day could actually be a number of other plants!
You would be surprised how many manufacturers sell you a four-leaf waterclover or a piece of oxalis foliage! Collected here for you are the factsabout true clover and the top four-leaf clover impersonators, so thisyear, you won’t be fooled!
An honest-to-goodness four-leaf clover is a rare variationof the authentic Irish Shamrock, a three-leafed clover produced by theherbaceous perennial, White Clover. Scientifically speaking, Trifoliumrepens.Literally translated, the scientific name means three leaves creeping – tri (fromthe Latin tres meaning three), folium (Latin meaning leaf) repens(Latin meaning creeping).
To find a real four-leaf clover, first you must identifythis typically three-leafed white clover and search carefully through themounds for the rare and lucky four-leafed variation. According toscientists, you have a one in ten thousand chance! For every four-leafclover that grows, ten thousand typical three leafed clovers exist.Considering how many parts of the world this hardy herbaceous plant isestablished, those aren’t terrible odds!
White clover contains 3 egg shapedleaflets that most often display a white watermark or herringbone imprint thatusually fold into a v-shape towards the base of each leaflet. When avariation occurs, the fourth leaf on a four-leaf-clover is usually noticeablysmaller than the other 3 leaves. Notice the leaflet in the bottom rightcorner of the four-leaf clover photograph above!
You may spot small, globe shapedwhite or pinkish-white florets shooting upwards from mounds (stands) of whiteclover on stalks that rise up from the leaf axles. The nectar from theseflowers is attractive to bees and especially to a particular case-bearer mothknown as Coleophora mayrella,who is so particular, it will only feed upon white clover. Note also thatyou may find small pods (legumes) roughly 4mm long if the season isright.
Aside from being endowed with the luckiest of reputations,white clover has a number of beneficial qualities. It is a hardygroundcover that can out-compete most other weeds you would otherwise findsettling into your lawn or turfgrass, which makes it a popular addition to yourlawn or grazing areas. It fixes nitrogen in the soil and it’s spreading,solid stands aid in the prevention of erosion, particularly on moist fertilesoil areas.
White clover is a popular forage cropfor livestock, popular among organic graziers and wandering Easter Bunnies.It grows in abundance, is high in proteins and tasty to the palette!Technically a legume, humans can ingest these plants as well. It isan often used survival plant, so if you find yourself lost in the woods or abear eats your granola on the next hiking escapade, you can fend off starvationand dehydration by munching on white clover leaves until help arrives.When eaten raw, the leaves may be difficult for human stomachs to digest, butcan be cooked (when in civilization) and added to salads or soups for a proteinboost and a happier belly.
Although it is not recommended in modern times, beforerefined medicines existed, white clover grew in abundance in a variety ofregions and was utilized as a medicinal plant by a number of Native Americantribes including the Cherokee, Delaware and Algonquin. All of these tribes preparedwhiteclover to make medicines that treated a number of ailments.
Trifolium repens' reputationgoes back even further to very ancient times. White clover was highlyregarded by the Druids in Ireland who believed the four leafed finds to be asign of luck, and would practice sacred rituals in groves where four-leafclovers were found. The Celts in Wales believed them to be a charmagainst evil spirits and would carry four leaf clovers with them on long,dangerous journeys for protection.
Until recently, there was a greatbotanical debate about what caused the four-leafed variations to grow withinthe three-leafed clover mounds. Some believed it was caused by somethingin the environment that triggered the variation. Some believed that itwas pure genetics, a recessive gene that appeared less often than a typicalrecessive variant. A third group of believers invested in the search forproof that the four leaves were caused by a mutation.
In 2010, researchers at the University of Georgia and the Samuel RobertsNoble Foundation in Ardmore, Oklahoma have started to put an end to this debateby publishing several exciting findings on the mysterious leaf traitinheritance in white clover in the July-August issue of Crop Science. Theresearchers discovered that there is a gene that turns ordinary three-leafclovers into the rare and sought after lucky four-leaf clovers. Thisgene is masked by the gene for three-leaflets, making it extra tricky to spot.Additionally, they discovered that the presence of the gene for the four-leaftrait is strongly influenced by the environmental conditions surrounding theplant, so practically everyone was right! Now that molecular markers are availableto detect the presence of the four-leaf gene, breeders can work with it,and who knows?! Soon, we may see the production of plants that produce truefour-leaf clovers in abundance!
FOUR-LEAF IMPERSONATORS
FAKER #1 Marsilea
Marsilea is a genus of approximately 65 species of aquatic ferns that belong to thefamily
Marsileaceae. Unlike your typicalfern, these multi-leaved pond plants have their own unique look. At theend of the long-stalks that shoot up from the water are leaves containing fourclover-like lobes that sit above the water surface, or submerged, depending onthe stage of plant growth. MarsileaquadrifoliaandMarsileapolycarpa are the biggest impostors of thisgenus, and resemble the four leaf clover so closely that many refer to these plantsas waterclover,most commonly, European waterclover.
Waterclover is found in many locations globallyincluding central and southern Europe, North America,Afghanistan,Southwest India, China, and Japan. Varieties of Marsilea have been wellestablished in the Northeastern States for over 100 years. Some culturesused the juice from this plant to treat snakebites and abscesses due to it'santi-inflamitory properties, which I suppose might make this a lucky plant ifyou've been bitten by a diamond back, however, it will not bring you the luckof the Irish.
FAKER #2 Oxalis
Thisimpostor is the easiest to discover. Oxalis is the largest ofthe genus within the Oxalidaceae (the wood-sorrel) family, containing 800 ofthe estimated 900 plants that fall under this family name. Numerousspecies of Oxalis have been referred to commonly asfalse shamrock, andfor good reason. From a distance they look like twins, unless they areflowering, which can make things easier. Most varieties sport 3 or 4 leaves andgrow in clumps that closely resemble white clover. Oxalis blooms inpinks, yellows and whites and the flowers are nothing like those of the whiteclover, making it easy to tell the difference.
A striking characteristic of this genus (and amajor reason for their name) is the oxalic acid they contain, giving the leavesand flowers a sour, tangy, acidic taste when chewed. This is reminiscentof Sorrel proper (Rumex acetosa) andexplains the common names given to many varieties, like wood sorrel or sourgrass.
* In very large amounts, oxalic acid may beconsidered slightly toxic to humans, interfering withproper digestion andkidney function. It should be noted, however, that the amount would have to beunusually large for a typical person in good health to feel effects. Oxalic acid is alsocontained inmorecommonly consumed foods at similar levels – including but not limitedto - spinach, broccoli, brusselsprouts, grapefruit, chives, and rhubarb.
Except for the Polar regions, many colorfulvarieties of Oxalis can be found most anywhere across the globe, and as aresult, it's been incorrectly identified as a four leaf clover in a variety ofcountries all over the world.
Now you know better, Philadelphia.
May the luck of the Irish be with you this Saint Patrick's Day!
Where To Go For More Information:
USDA Fact Sheet on Trifolium repens L. (WhiteClover)
To purchase the article or review the abstract fromCrop Science:
Journal reference: Crop Science, DOI:10.2135/cropsci2009.08.0457
Virginia Tech Weed Identification Guide (eventhough it's not technically a weed!)