| Bay laurel | |
|---|---|
| Bay laurel (Laurus nobilis) flower buds and leaves | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Magnoliids |
| Order: | Laurales |
| Family: | Lauraceae |
| Genus: | Laurus |
| Species: | L. nobilis |
| Binomial name | |
| Laurus nobilis L. |
|
The bay laurel (Laurus nobilis, of the plant family Lauraceae), also known as sweet bay, bay tree, true laurel, Grecian laurel, laurel tree, or simply laurel, is an aromatic evergreen tree or large shrub with green, glossy leaves, native to the Mediterranean region. It is the source of the bay leaf used in cooking. Under the simpler name "laurel," Laurus nobilis figures prominently in classical Greek, Roman, and Biblical culture.
Worldwide, many other kinds of plants in diverse families are also called "bay" or "laurel," generally due to similarity of foliage or aroma to Laurus nobilis, and the full name is used for the California bay laurel (Umbellularia), also in the family Lauraceae.
Contents |
The laurel can vary greatly in size and height, sometimes reaching 10–18 metres (33–59 ft) tall. Laurus is a genus of evergreen trees belonging to the Laurel family, Lauraceae. The genus includes three species, whose diagnostic key characters often overlap (Mabberley 1997).
The laurel is dioecious (unisexual), with male and female flowers on separate plants.[1] Each flower is pale yellow-green, about 1 cm diameter, and they are born in pairs beside a leaf. The leaves are 6–12 cm long and 2–4 cm broad, with a characteristic finely-serrated and wrinkled margin. The fruit is a small, shiny black berry about 1 cm long.[1]
Laurus nobilis and Ilex aquifolium are widespread relics of the laurisilva forests that originally covered much of the Mediterranean Basin when the climate of the region was more humid. With the drying of the Mediterranean during the Pliocene era, the laurel forests gradually retreated, and were replaced by the more drought-tolerant sclerophyll plant communities familiar today. Most of the last remaining laurisilva forests around the Mediterranean are believed to have disappeared approximately ten thousand years ago at the end of the Pleistocene era, when the Mediterranean Basin became drier and with a harsher climate, although some remnants of the laurel forest flora still persist in the mountains of southern Turkey, northern Syria, southern Spain, north-central Portugal and northern Morocco. Indigenous laurisilva forest also persists in Madeira near the North Atlantic Ocean, which has moderated these climatic fluctuations.
The ecological requirements of the species, are those of the laurel forest and like most of their counterparts laurifolia in the world, it is vigorous species with a great ability to populate the habitat that is conducive. Laurus nobilis responded to favourable climatic periods and expanded across the available habitat. Laurus nobilis occur as opportunistic species across wide distribution with close relatives and few species, indicating the recent divergence of this species. The extant laurel species of this group are relatively young.
The laurus genus is characteristic of the formations of laurel forest and was more widespread in the Tertiary. It has led to endemic species on islands, but not so widespread geographically as in the past. The genus come from a few relict species living in temperate areas and more distributed in the Tertiary. The main centers are found inhabiting montane forests or coastal forest in low-altitude. Laurus nobilis species have adapted to more extreme conditions but mostly depending on favorable soil edaphic conditions, as presence of aquifers, groundwater periodic flows, etc.
The patterns of speciation in the Lauraceae family, where laurus genus belong, indicate that since the onset of aridification on the continents 15 million years ago, rainforest diversified in species numbers with the majority of species the product of vicariance. One of the products of aridification is the current island like archipelagos of rainforests along the planet. The fragmentation of once more continuous rainforest facilitated isolation of populations and this likely caused the increase in the rate of speciation as found in the Lauraceae. In Europe the genus is represented by a single species, the named Laurus nobilis. In macaronesian islands this former arose from a common ancestor in the area of laurisilva in the Mediterranean area. The islander laurels of Macaronesia in the eastern Atlantic, are closely related to this species. A recent study found that native stands classified as L. nobilis in northern Spain shared greater genetic and morphological similarity to L. azorica than to populations of L. nobilis native to rest of Spain, France and Italy [Arroyo-Garcia et al. 2001]. This populations like the Cortegada Island population, in Galicia, famous for its large grove of laurels, come from seeds dispersed by birds but is not indigenous to the island, as this islander forest originated spontaneously from laurel specimens that were planted after the original vegetation was destroyed.
Fossils dating from before the Pleistocene glaciations show that species of Laurus were formerly distributed more widely around the Mediterranean and North Africa, when the climate was more humid and mild than at present. It is currently thought that the drying of the Mediterranean basin during the glaciations caused Laurus to retreat to the mildest climate refuges, including southern Spain, Portugal and the Macaronesian islands. With the end of the last glacial period, L. nobilis recovered some of its former range around the Mediterranean.
The most abundant essential oil found in laurel is cineole, also called eucalyptol.[1] The leaves contain about 1.3% essential oils (ol. lauri folii), consisting of 45% eucalyptol, 12% terpenes, 3-4% sesquiterpenes, 3% methyleugenol, and other α- und β-pinenes, phellandrene, linalool, geraniol, and terpineol.
Both essential and fatty oils are present in the fruit. The fruit is pressed and water-extracted to obtain these products. The fruit contains up to 30% fatty oils and about 1% essential oils (terpenes, sesquiterpenes, alcohols, and ketones).
The plant is the source of several popular spices used in a wide variety of recipes, particularly among Mediterranean cuisines.[1] Most commonly, the aromatic leaves are used, fresh or dried. For cooking purposes, whole bay leaves have a long shelf life of about one year, under normal temperature and humidity.[2] Bay leaves are used almost exclusively as flavour agents during the food preparation stage; even when cooked, whole bay leaves can be sharp and abrasive enough to damage internal organs, so they are typically removed from dishes before serving, unless used as a simple garnish.[2]
Ground bay leaves, however, can be ingested safely and are often used in soups and stocks, as well as being a common addition to a Bloody Mary.[2] Dried laurel berries and pressed leaf oil can both be used as robust spices, and even the wood can be burnt for strong smoke flavouring.[2]
Aqueous extracts of bay laurel can also be used as astringents and even as a reasonable salve for open wounds.[3]
In massage therapy, the essential oil of bay laurel is reputed to alleviate arthritis and rheumatism, while in aromatherapy, it is used to treat earaches and high blood pressure.[4] A traditional folk remedy for rashes caused by poison ivy, poison oak, and stinging nettle is a poultice soaked in boiled bay leaves.[5]
The chemical compound lauroside B isolated from Laurus nobilis is an inhibitor of human melanoma (skin cancer) cell proliferation at high concentrations.[6]
Laurel is widely cultivated as an ornamental plant in regions with Mediterranean or oceanic climates, and as a house plant or greenhouse plant in colder regions.
Laurel oil is a main ingredient, and the distinguishing characteristic of Aleppo soap. Aleppo soap is revered worldwide for its skin care properties.
Bay laurel was used to fashion the laurel wreath of ancient Greece, a symbol of highest status. A wreath of bay laurels was given as the prize at the Pythian Games because the games were in honor of Apollo, and the laurel was one of his symbols.
Ovid tells the story that laurel tree was first formed when the nymph Daphne was changed into a laurel tree because of Apollo's pursuit of her. Daphne is the Greek name for the tree.[7]
The symbolism carried over to Roman culture, which held the laurel as a symbol of victory.[8] It is also the source of the words baccalaureate and poet laureate, as well as the expressions "assume the laurel" and "resting on one's laurels".
In the Bible, the laurel is often an emblem of prosperity and fame. In Christian tradition, it symbolizes the resurrection of Christ.
In Chinese folklore, there is a great laurel tree on the moon, and the Chinese name for the laurel, (Chinese: 月桂), literally translates to "moon-laurel". This is the subject of a story of Wu Gang, a man who aspired to immortality and neglected his work. When the deities discovered this, they sentenced Wu Gang to fell the laurel tree, whereupon he could join the ranks of the deities; however, since the laurel regenerated immediately when cut, it could never be felled. The phrase (Chinese: 吴刚伐木) ("Wu Gang chops the tree") is sometimes used to refer to endless toil, analogous to the legend of Sisyphus in Greek mythology.