[citation needed] Because the family is so ancient and was so widely distributed on the Gondwana supercontinent, modern species commonly occur in relict populations isolated by geographical barriers, for instance on islands or tropical mountains.

Relict forests retain endemic fauna and flora in communities of great value in inferring the palaeontological succession and climate change that followed the breakups of the supercontinents.

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.

[citation needed] Other birds that rely heavily on the fruit for their diets include members of the families Cotingidae, Columbidae, Trogonidae, Turdidae, and Ramphastidae, amongst others.

Seed dispersal of various species in the family is also carried out by monkeys, arboreal rodents, porcupines, opossums, and fishes.

Other lauraceous species, members of the genus Pleurothyrium in particular, have a symbiotic relationship with ants that protect and defend the tree.

[14] Defense mechanisms that occur among members of the Lauraceae include irritant or toxic sap or tissues that repel or poison many herbivorous organisms.

Other members of the family however, occur pantropically in general lowland and Afromontane forest, and in Africa for example there are species endemic to countries such as Cameroon, Sudan, Tanzania, Uganda and Congo.

Scientific names similar to Daphne (e.g., Daphnidium, Daphniphyllum)[15] or "laurel" (e.g.,Laureliopsis, Skimmia laureola) indicate other plant families that resemble Lauraceae.

[16] Paleobotanists have suggested the family originated some 174±32 million years ago (Mya), while others[17] do not believe they are older than the mid-Cretaceous.

Fossil flowers attributed to this family occur in Cenomanian clays (mid-Cretaceous, 90-98 Mya) of the Eastern United States (Mauldinia mirabilis).

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.

[24] All available evidence, except for inflorescence morphology and wood and bark anatomy, fails to support separate tribes Laureae and Perseeae.

[26] Additionally, the huge amount of variation within the family poses a major challenge for developing a reliable classification.

[21][27] 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.

Lignans and neolignans are present, along with S-methyl-5-O-flavonoids, proanthocyanidins, cinnamoylamides, phenylpyrroles, styryl pyrones, polyketides (acetogenins), furanosesquiterpenes, and germacranolidous, heliangolidous, eudesmanolidous and guaianolidous sesquiterpene lactones.

[citation needed] Recent taxonomic revisions of the family include these genera:[28] These genera have traditionally been considered separate within Lauraceae, but have not been included in the most recent treatments: A laurel wreath, a round or horseshoe-shaped wreath made of connected laurel branches and leaves, is an ancient symbol of triumph in classical Western culture originating in Greek mythology, and is associated in some countries with academic or literary achievement.