Lauraceae, or the laurels, is a plant

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

that includes the true laurel and its closest relatives. This family comprises about 2850 known species in about 45

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

worldwide. They are

dicotyledon The dicotyledons, also known as dicots (or, more rarely, dicotyls), are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, ...

s, and occur mainly in warm temperate and tropical regions, especially

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. Many are aromatic

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

trees or shrubs, but some, such as '' Sassafras'', are

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

, or include both deciduous and evergreen trees and shrubs, especially in tropical and temperate climates. The genus '' Cassytha'' is unique in the Lauraceae in that its members are

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

vine A vine is any plant with a growth habit of trailing or scandent (that is, climbing) stems, lianas, or runners. The word ''vine'' can also refer to such stems or runners themselves, for instance, when used in wicker work.Jackson; Benjamin; Da ...

s. Most laurels are highly poisonous.

Overview

The family has a worldwide distribution in tropical and warm climates. The Lauraceae are important components of tropical

forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...

s ranging from low-lying to

montane Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures lapse rate, fall as elevation increases, causing the ecosystem to stratify. This stratification is ...

. In several forested regions, Lauraceae are among the top five families in terms of the number of species present. The Lauraceae give their name to habitats known as

laurel forest Laurel forest, also called laurisilva or laurissilva, is a type of subtropical forest found in areas with high humidity and relatively stable, mild temperatures. The forest is characterized by broadleaf tree species with evergreen, glossy and el ...

s, which have many trees that superficially resemble the Lauraceae, though they may belong to other plant families such as

Magnoliaceae The Magnoliaceae () are a flowering plant family, the magnolia family, in the order Magnoliales. It consists of two genera: '' Magnolia'' and ''Liriodendron'' (tulip trees). Unlike most angiosperms, whose flower parts are in whorls (rings), ...

Myrtaceae Myrtaceae (), the myrtle family, is a family of dicotyledonous plants placed within the order Myrtales. Myrtle, pōhutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus are some notable members of this group. All ...

. Laurel forests of various types occur on most continents and on many major islands. Although the taxonomy of the Lauraceae is still not settled, conservative estimates suggest some 52 genera worldwide, including 3,000 to 3,500 species. Compared to other plant families, the taxonomy of Lauraceae still is poorly understood. This is partly due to its great diversity, the difficulty of identifying the species, and partly because of inadequate investment in taxonomic work. Recent monographs on small and medium-sized genera of Lauraceae (up to about 100 species) have revealed many new species. Similar increases in the numbers of species recognised in other larger genera are to be expected.

Description

Most of the Lauraceae are evergreen

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

s in

habit A habit (or wont, as a humorous and formal term) is a routine of behavior that is repeated regularly and tends to occur subconsciously. A 1903 paper in the '' American Journal of Psychology'' defined a "habit, from the standpoint of psychology, ...

. Exceptions include some two dozen species of '' Cassytha'', all of which are obligately

s. The fruits of Lauraceae are

drupe In botany, a drupe (or stone fruit) is a type of fruit in which an outer fleshy part (exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pip'' (UK), ''pit'' (US), ''stone'', or ''pyrena'') of hardened endocarp with a seed ...

s, one-seeded fleshy fruit with a hard layer, the

endocarp Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Fruitlike structures may develop directly from the seed itself rather th ...

, surrounding the seed. However, the endocarp is very thin, so the fruit resemble a one-seeded berry. The fruit in some species (particularly in the genera '' Ocotea'') are partly immersed or covered in a cup-shaped or deep thick cupule, which is formed from the tube of the calyx where the peduncle joins the fruit; this gives the fruit an appearance similar to an

acorn The acorn is the nut (fruit), nut of the oaks and their close relatives (genera ''Quercus'', ''Notholithocarpus'' and ''Lithocarpus'', in the family Fagaceae). It usually contains a seedling surrounded by two cotyledons (seedling leaves), en ...

. In some ''

Lindera Dried fruits of ''Lindera neesiana'' used as spice (coll. MHNT) ''Lindera'' is a genus of about 80–100hypocarpium at the base of the fruit.

Distribution and uses

Because the family is so ancient and was so widely distributed on the

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continent, continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", ...

, modern species commonly occur in

relict A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...

populations isolated by geographical barriers, for instance on islands or tropical mountains. Relict forests retain

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

fauna Fauna (: faunae or faunas) is all of the animal life present in a particular region or time. The corresponding terms for plants and fungi are ''flora'' and '' funga'', respectively. Flora, fauna, funga and other forms of life are collectively ...

and

flora Flora (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...

in communities of great value in inferring the

palaeontological Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

succession and

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

that followed the breakups of the supercontinents. *Many Lauraceae contain high concentrations of

essential oils An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the o ...

, some of which are valued for spices and perfumes. Within the plants, most such substances are components of irritant or toxic sap or tissues that repel or poison many

herbivorous A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n ...

or parasitic organisms. *Some of the essential oils are valued as

fragrances An aroma compound, also known as an odorant, aroma, fragrance, flavoring or flavor, is a chemical compound that has a smell or odor. For an individual chemical or class of chemical compounds to impart a smell or fragrance, it must be sufficien ...

, such as in the traditional

laurel wreath A laurel wreath is a symbol of triumph, a wreath (attire), wreath made of connected branches and leaves of the bay laurel (), an aromatic broadleaf evergreen. It was also later made from spineless butcher's broom (''Ruscus hypoglossum'') or cher ...

classical antiquity Classical antiquity, also known as the classical era, classical period, classical age, or simply antiquity, is the period of cultural History of Europe, European history between the 8th century BC and the 5th century AD comprising the inter ...

, or in

cabinet making A cabinet is a case or cupboard with shelves or drawers for storing or displaying items. Some cabinets are stand alone while others are built in to a wall or are attached to it like a medicine cabinet. Cabinets are typically made of wood (solid ...

, where the fragrant woods are prized for making insect-repellant furniture chests. *Some are valued in cooking, for example,

bay leaves The bay leaf is an aromatic leaf commonly used as a herb in cooking. It can be used whole, either dried or fresh, in which case it is removed from the dish before consumption, or less commonly used in ground form. The flavour that a bay leaf ...

are a popular ingredient in European, American, and Asian cuisines. *Avocados are important oil-rich fruit that are cultivated in warm climates around the world. *Many species are exploited for

timber Lumber is wood that has been processed into uniform and useful sizes (dimensional lumber), including beams and planks or boards. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, window frames). ...

. *Some species are valued as sources of medicinal material. These genera include some of the best-known species of particular commercial value: *''

Cinnamomum ''Cinnamomum'' is a genus of evergreen aromatic trees and shrubs belonging to the laurel family, Lauraceae. The species of ''Cinnamomum'' have aromatic oils in their leaves and bark. The genus contains approximately 234 species, distributed in ...

'':

cinnamon Cinnamon is a spice obtained from the inner bark of several tree species from the genus ''Cinnamomum''. Cinnamon is used mainly as an aromatic condiment and flavouring additive in a wide variety of cuisines, sweet and savoury dishes, biscuits, b ...

(''Cinnamonum verum'') and cassia (''Cinnamomum cassia'') *'' Camphora'':

camphor tree ''Camphora officinarum'' is a species of evergreen tree indigenous to warm temperate to subtropical regions of East Asia, including countries such as China, Taiwan, Vietnam, Korea, and Japan. It is known by various names, most notably the camph ...

(''Camphora officinarum'') *'' Laurus'':

bay laurel ''Laurus nobilis'' is an aromatic evergreen tree or large shrub with green, glabrous (smooth) leaves. It is in the flowering plant family Lauraceae. According to Flora Cretica (Kleinsteuber Books, 2024, ISBN 978-3-9818110-5-6) the stem can be 1 ...

(''Laurus nobilis'') *''

Persea ''Persea'' is a genus of about 111 species of evergreen trees belonging to the laurel family, Lauraceae. The best-known member of the genus is the avocado, ''P. americana'', widely cultivated in subtropical regions for its large, edible fruit. O ...

'':

avocado The avocado, alligator pear or avocado pear (''Persea americana'') is an evergreen tree in the laurel family (Lauraceae). It is native to Americas, the Americas and was first domesticated in Mesoamerica more than 5,000 years ago. It was priz ...

(''Persea americana'')

Loss of habitat Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

and

overexploitation Overexploitation, also called overharvesting or ecological overshoot, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to ...

for such products has put many species in

danger Danger is a lack of safety and may refer Places * Danger Cave, an archaeological site in Utah * Danger Island, Great Chagos Bank, Indian Ocean * Danger Island, alternate name of Pukapuka Atoll in the Cook Islands, Pacific Ocean * Danger Island ...

of extinction as a result of overcutting, extensive

illegal logging Illegal logging is the harvest, transportation, purchase, or sale of timber in violation of laws. The harvesting procedure itself may be illegal, including using corrupt means to gain access to forests; extraction without permission, or from a p ...

, and habitat conversion. Conversely, some species, though commercially valuable in some countries, are regarded as aggressive invaders in other regions. For example, ''Cinnamomum camphora'', though a valued ornamental and medicinal plant, is so invasive as to have been declared a weed in subtropical forested areas of South Africa.

Ecology

Lauraceae flowers are protogynous, often with a complex flowering system to prevent

inbreeding Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely genetic distance, related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genet ...

. The fruits are an important food source for birds, on which some

Palaeognathae Palaeognathae (; ) is an infraclass of birds, called paleognaths or palaeognaths, within the class Aves of the clade Archosauria. It is one of the two extant taxon, extant infraclasses of birds, the other being Neognathae, both of which form Neo ...

are highly dependent. Other birds that rely heavily on the fruit for their diets include members of the families Cotingidae,

Columbidae Columbidae is a bird Family (biology), family consisting of doves and pigeons. It is the only family in the Order (biology), order Columbiformes. These are stout-bodied birds with small heads, relatively short necks and slender bills that in ...

, Trogonidae,

Turdidae The thrushes are a passerine bird family, Turdidae, with a worldwide distribution. The family was once much larger before biologists reclassified the former subfamily Saxicolinae, which includes the chats and European robins, as Old World flyca ...

, and Ramphastidae, amongst others. Birds that are specialised frugivores tend to eat the whole fruit and regurgitate seeds intact, thereby releasing the seeds in favourable situations for germination ( ornithochory). Some other birds that swallow the fruit pass the seed intact through their guts.

Seed dispersal In spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, ...

of various species in the family is also carried out by

monkey Monkey is a common name that may refer to most mammals of the infraorder Simiiformes, also known as simians. Traditionally, all animals in the group now known as simians are counted as monkeys except the apes. Thus monkeys, in that sense, co ...

arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally (scansorial), but others are exclusively arboreal. The hab ...

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

porcupine Porcupines are large rodents with coats of sharp Spine (zoology), spines, or quills, that protect them against predation. The term covers two Family (biology), families of animals: the Old World porcupines of the family Hystricidae, and the New ...

opossum Opossums () are members of the marsupial order Didelphimorphia () endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 126 species in 18 genera. Opossums originated in South America and entered North A ...

s, and

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

es.

Hydrochory In spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors ...

occurs in '' Caryodaphnopsis''. The leaves of some species in the Lauraceae have

domatia A domatium (plural: domatia, from the Latin "domus", meaning home) is a tiny chamber that houses arthropods, produced by a plant. Ideally domatia differ from galls in that they are produced by the plant rather than being induced by their inhabi ...

in the axils of their

veins Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and fetal c ...

. The domatia are home to certain

mite Mites are small arachnids (eight-legged arthropods) of two large orders, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari. However, most recent genetic analyses do not recover the two as eac ...

s. Other lauraceous species, members of the genus '' Pleurothyrium'' in particular, have a

symbiotic Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...

relationship with ants that protect and defend the tree. Some '' Ocotea'' species are also used as nesting sites by ants, which may live in leaf pockets or in hollowed-out stems. Defense mechanisms that occur among members of the Lauraceae include irritant or toxic sap or tissues that repel or poison many

organisms. Trees of the family predominate in the world's

s and

cloud forest A cloud forest, also called a water forest, primas forest, or tropical montane cloud forest, is a generally tropical or subtropical, evergreen, Montane forest, montane, Tropical and subtropical moist broadleaf forests, moist forest characteri ...

s, which occur in tropical to mild temperate regions of both northern and southern hemispheres. Other members of the family however, occur pantropically in general lowland and

Afromontane The Afromontane regions are subregions of the Afrotropical realm, one of the Earth's eight biogeographic realms, covering the plant and animal species found in the mountains of Africa and the southern Arabian Peninsula. The Afromontane regions o ...

forest, and in Africa for example there are species endemic to countries such as

Cameroon Cameroon, officially the Republic of Cameroon, is a country in Central Africa. It shares boundaries with Nigeria to the west and north, Chad to the northeast, the Central African Republic to the east, and Equatorial Guinea, Gabon, and the R ...

Sudan Sudan, officially the Republic of the Sudan, is a country in Northeast Africa. It borders the Central African Republic to the southwest, Chad to the west, Libya to the northwest, Egypt to the north, the Red Sea to the east, Eritrea and Ethiopi ...

Tanzania Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to t ...

Uganda Uganda, officially the Republic of Uganda, is a landlocked country in East Africa. It is bordered to the east by Kenya, to the north by South Sudan, to the west by the Democratic Republic of the Congo, to the south-west by Rwanda, and to the ...

and Congo. Several

species in the Lauraceae occur in temperate areas of both hemispheres. Many botanical species in other families have similar foliage to the Lauraceae due to

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

, and forests of such plants are called

. These plants are adapted to high rainfall and humidity, and have leaves with a generous layer of wax, making them glossy in appearance, and a narrow, pointed-oval shape with a 'drip tip', which permits the leaves to shed water despite the humidity, allowing transpiration to continue. Scientific names similar to ''

Daphne Daphne (; ; , , ), a figure in Greek mythology, is a naiad, a variety of female nymph associated with fountains, wells, springs, streams, brooks and other bodies of freshwater. There are several versions of the myth in which she appears, but t ...

'' (e.g., '' Daphnidium'', ''

Daphniphyllum ''Daphniphyllum'' is the sole genus in the flowering plant family Daphniphyllaceae and was described as a genus in 1826. The genus includes evergreen shrubs and trees mainly native to east and southeast Asia, but also found in the Indian Subconti ...

'') or "laurel" (e.g.,'' Laureliopsis'', '' Skimmia laureola'') indicate other plant families that resemble Lauraceae. Some Lauraceae species have adapted to demanding conditions in semiarid climates, but they tend to depend on favorable edaphic conditions, for example, perennial aquifers, periodic groundwater flows, or periodically flooded forests in sand that contains hardly any nutrients. Various species have adapted to swampy conditions by growing pneumatophores, roots that grow upward, that project above the levels of periodic floods that drown competing plants which lack such adaptations.

Paleobotanists Paleobotany or palaeobotany, also known as paleophytology, is the branch of botany dealing with the recovery and identification of plant fossils from geological contexts, and their use for the biological reconstruction of past environments (pale ...

have suggested the family originated some 174±32 million years ago (Mya), while others do not believe they are older than the mid-

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

. Fossil flowers attributed to this family occur in

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

clays (mid-Cretaceous, 90-98 Mya) of the Eastern

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

(''Mauldinia mirabilis''). Fossils of Lauraceae are common in the Tertiary strata of Europe and North America, but they virtually disappeared from central Europe in the Late

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

. Because of their unusual fragility, the pollens of Lauraceae do not keep well and have been found only in relatively recent strata. Deciduous Lauraceae lose all of their leaves for part of the year depending on variations in rainfall. The leaf loss coincides with the

dry season The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The t ...

in tropical, subtropical, and arid regions. Laurel wilt disease, caused by the virulent fungal pathogen ''Raffaelea lauricola'', a native of southern Asia, was found in the southeast United States in 2002. The fungus spreads between hosts via a wood-boring beetle, '' Xyleborus glabratus'', with which it has a

symbiotic Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...

relationship. Several Lauraceae species are affected. The beetle and disease are believed to have arrived in the US via infected solid wood packing material, and have since spread to several states.

Classification

Classification within the Lauraceae is not fully resolved. Multiple classification schemes based on a variety of morphological and anatomical characteristics have been proposed, but none are fully accepted. According to Judd et al. (2007), the suprageneric classification proposed by van der Werff and Richter (1996) is currently the authority. However, due to an array of molecular and embryological evidence that disagrees with the groupings, it is not fully accepted by the scientific community. Their classification is based on inflorescence structure and wood and bark anatomy. It divides Lauraceae into two subfamilies, Cassythoideae and Lauroideae. The Cassythoideae comprise a single genus, ''Cassytha'', and are defined by their herbaceous, parasitic habit. The Lauroideae are then divided into three tribes: Laureae, Perseeae, and Cryptocaryeae. The subfamily Cassythoideae is not fully supported. Backing has come from ''matK'' sequences of chloroplast genes while a questionable placement of ''Cassytha'' has been concluded from analysis of intergenetic spacers of chloroplast and nuclear genomes. Embryological studies also appear contradictory. One study by Heo et al. (1998) supports the subfamily. It found that ''Cassytha'' develops an ''ab initio'' cellular-type endosperm and the rest of the family (with one exception) develops a nuclear-type endosperm. Kimoto et al. (2006) suggest ''Cassytha'' should be placed in the tribe Cryptocaryeae because it shares a glandular anther tapetum and an embryo sac protruding from the nucellus with other members of the Cryptocaryeae. The tribes Laureae and Perseeae are not well supported by any molecular or embryological studies. Sequences of the ''matK'' chloroplast gene, as well as sequences of chloroplast and nuclear genomes, reveal close relationships between the two tribes. Embryological evidence does not support a clear division between the two tribes, either. Genera such as ''Caryodaphnopsis'' and ''Aspidostemon'' that share embryological characteristics with one tribe and wood and bark characteristics or inflorescence characteristics with another tribe blur the division of these groups. All available evidence, except for inflorescence morphology and wood and bark anatomy, fails to support separate tribes Laureae and Perseeae. The tribe Cryptocaryeae is partially supported by molecular and embryological studies. Chloroplast and nuclear genomes support a tribal grouping that contains all the genera circumscribed by van der Weff and Richter (1996), as well as three additional genera. Partial support for the tribe is also attained from the ''matK'' sequences of chloroplast genes as well as embryology. Challenges in Lauraceae classification The knowledge of the species comprising the Lauraceae is incomplete. In 1991, about 25-30% of neotropical Lauraceae species had not been described. In 2001, embryological studies had only been completed on individuals from 26 genera yielding a 38.9% level of knowledge, in terms of embryology, for this family. Additionally, the huge amount of variation within the family poses a major challenge for developing a reliable classification.

Phytochemistry

The adaptation of Lauraceae to new environments has followed a long evolutionary journey which has led to many specializations, including defensive or deterrent systems against other organisms. Phytochemicals in the Lauraceae are numerous and diverse. Benzylisoquinoline

alkaloid Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large varie ...

s include aporphines and oxoaporphines, as well as derivatives of morphinans. Essential oils include

terpenoid The terpenoids, also known as isoprenoids, are a class of naturally occurring organic compound, organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeabl ...

s, benzyl benzoates, allylphenols, and propenylphenols.

Lignan The lignans are a large group of low molecular weight polyphenols found in plants, particularly seeds, whole grains, and vegetables. The name derives from the Latin word for "wood". Lignans are precursors to phytoestrogens. They may play a rol ...

s and neolignans are present, along with ''S''-methyl-5-O-

flavonoid Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

proanthocyanidin Proanthocyanidins are a class of polyphenols found in many plants, such as cranberry, blueberry, and grape seeds. Chemically, they are oligomeric flavonoids. Many are oligomers of catechin and epicatechin and their gallic acid esters. More complex ...

s, cinnamoylamides, phenylpyrroles, styryl pyrones,

polyketide In organic chemistry, polyketides are a class of natural products derived from a Precursor (chemistry), precursor molecule consisting of a Polymer backbone, chain of alternating ketone (, or Carbonyl reduction, its reduced forms) and Methylene gro ...

s (

acetogenin Acetogenins are a class of polyketide natural products found in plants of the family Annonaceae. They are characterized by linear 32- or 34-carbon chains containing oxygenated functional groups including hydroxyls, ketones, epoxides, tetrahyd ...

s), furanosesquiterpenes, and germacranolidous, heliangolidous, eudesmanolidous and guaianolidous

sesquiterpene lactones Sesquiterpene lactones (SLs) are a class of sesquiterpenoids that contain a lactone ring. They are most often found in plants of the family Asteraceae (daisies, asters). Other plant families with SLs are Umbelliferae (celery, parsley, carrots) ...

Genera

58 genera are accepted.

Popular culture

, a round or horseshoe-shaped

wreath A wreath () is an assortment of flowers, leaves, fruits, twigs, or various materials that is constructed to form a ring shape. In English-speaking countries, wreaths are used typically as household ornaments, most commonly as an Advent and C ...

made of connected laurel branches and leaves, is an ancient symbol of triumph in classical Western culture originating in

Greek mythology Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of ancient Greek folklore, today absorbed alongside Roman mythology into the broader designation of classical mythology. These stories conc ...

, and is associated in some countries with academic or literary achievement.