Laurales
Encyclopedia
The Laurales are an order of flowering plant
s. They are magnoliids, related to the Magnoliales
.
The order includes about 2500-2800 species from 85-90 genera, which comprise seven families of tree
s and shrub
s. Most of the species are tropical and subtropical, though a few genera reach the temperate zone. The best known species in this order are those of the Lauraceae
(for example bay laurel
, cinnamon
, avocado
, and Sassafras
), and the ornamental shrub Calycanthus
of the Calycanthaceae.
The earliest lauraceous fossil
s are from to the early Cretaceous
. It is possible that the ancient origin of this order is one of the reasons for its highly diverged morphology. Indeed, presently no single morphological property is known, which would unify all the members of Laurales. The presently accepted classification is based on molecular and genetic analysis.
. During some or all of the 20th century, the Laurales generally included Amborella
and the plants now classified in Austrobaileyales
and Chloranthaceae
. They were not removed until the advent of molecular data in the late 20th century; their previous inclusion made it harder to determine the relationships within the Laurales and between the Laurales and other groups.
The following families are included in the Angiosperm Phylogeny Group
system:
Under the older Cronquist system
, the Laurales included a slightly different set of families (current placement, where different, in brackets):
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
s. They are magnoliids, related to the Magnoliales
Magnoliales
Magnoliales is an order of flowering plants.-Classification:The Magnoliales includes six families:* Annonaceae...
.
The order includes about 2500-2800 species from 85-90 genera, which comprise seven families of tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s and shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s. Most of the species are tropical and subtropical, though a few genera reach the temperate zone. The best known species in this order are those of the Lauraceae
Lauraceae
The Lauraceae or Laurel family comprises a group of flowering plants included in the order Laurales. The family contains about 55 genera and over 3500, perhaps as many as 4000, species world-wide, mostly from warm or tropical regions, especially Southeast Asia and South America...
(for example bay laurel
Bay Laurel
The bay laurel , 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...
, cinnamon
Cinnamon
Cinnamon is a spice obtained from the inner bark of several trees from the genus Cinnamomum that is used in both sweet and savoury foods...
, avocado
Avocado
The avocado is a tree native to Central Mexico, classified in the flowering plant family Lauraceae along with cinnamon, camphor and bay laurel...
, and Sassafras
Sassafras
Sassafras is a genus of three extant and one extinct species of deciduous trees in the family Lauraceae, native to eastern North America and eastern Asia.-Overview:...
), and the ornamental shrub Calycanthus
Calycanthus
Calycanthus is a genus of flowering plants in the family Calycanthaceae, endemic to North America. The genus includes two to four species depending on taxonomic interpretation; two are accepted by the Flora of North America....
of the Calycanthaceae.
The earliest lauraceous fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s are from to the early Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
. It is possible that the ancient origin of this order is one of the reasons for its highly diverged morphology. Indeed, presently no single morphological property is known, which would unify all the members of Laurales. The presently accepted classification is based on molecular and genetic analysis.
Classification
The first botanist to think of the Laurales as a natural group was H. Hallier in 1905. He viewed them as being derived from the MagnolialesMagnoliales
Magnoliales is an order of flowering plants.-Classification:The Magnoliales includes six families:* Annonaceae...
. During some or all of the 20th century, the Laurales generally included Amborella
Amborella
Amborella is a genus of rare understory shrubs or small trees endemic to the island of New Caledonia. The genus consists of only a single species, Amborella trichopoda, and is the only member of the family Amborellaceae. Wood of Amborella lacks the vessels characteristic of most flowering plants...
and the plants now classified in Austrobaileyales
Austrobaileyales
Austrobaileyales is the botanical name for an order of flowering plants, consisting of about 100 species of woody plants, perhaps the most famous of which is the spice star anise.- In different classifications :...
and Chloranthaceae
Chloranthaceae
Chloranthaceae is the botanical name of a family of flowering plants. The family consists of four genera, totalling several dozen species, of herbaceous or woody plants occurring in Southeast Asia, the Pacific, Madagascar, Central & South America, and the West Indies...
. They were not removed until the advent of molecular data in the late 20th century; their previous inclusion made it harder to determine the relationships within the Laurales and between the Laurales and other groups.
The following families are included in the Angiosperm Phylogeny Group
Angiosperm Phylogeny Group
The Angiosperm Phylogeny Group, or APG, refers to an informal international group of systematic botanists who came together to try to establish a consensus on the taxonomy of flowering plants that would reflect new knowledge about plant relationships discovered through phylogenetic studies., three...
system:
order Laurales
|
{clade| style=font-size:75%;line-height:75% | label1=Magnoliidae Magnoliidae Magnoliids are a group of about 9,000 species of flowering plants, including magnolias, nutmeg, bay laurel, cinnamon, avocado, black pepper, and many others. They are characterized by trimerous flowers, pollen with one pore, and usually branching-veined leaves.-Classification:Traditionally,... |
1= }} |
| The current composition and phylogeny Phylogenetics In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices... of the Laurales. |
|||
Under the older Cronquist system
Cronquist system
The Cronquist system is a taxonomic classification system of flowering plants. It was developed by Arthur Cronquist in his texts An Integrated System of Classification of Flowering Plants and The Evolution and Classification of Flowering Plants .Cronquist's system places flowering plants into two...
, the Laurales included a slightly different set of families (current placement, where different, in brackets):
- Family AmborellaAmborellaAmborella is a genus of rare understory shrubs or small trees endemic to the island of New Caledonia. The genus consists of only a single species, Amborella trichopoda, and is the only member of the family Amborellaceae. Wood of Amborella lacks the vessels characteristic of most flowering plants...
ceae (Family AmborellaAmborellaAmborella is a genus of rare understory shrubs or small trees endemic to the island of New Caledonia. The genus consists of only a single species, Amborella trichopoda, and is the only member of the family Amborellaceae. Wood of Amborella lacks the vessels characteristic of most flowering plants...
ceae, unplaced) - Family CalycanthaceaeCalycanthaceaeThe Calycanthaceae is a small family of flowering plants included in the order Laurales. The family contains four genera and only 6-11 species, restricted to warm temperate and tropical regions:...
- Family Gomortegaceae
- Family HernandiaceaeHernandiaceaeHernandiaceae is the botanical name for a family of flowering plants. Such a family has been recognised by most taxonomists.The APG II system, of 2003 , also recognizes this family, and assigns it to the order Laurales in the clade magnoliids...
- Family Idiospermaceae (= Calycanthaceae pro parte)
- Family LauraceaeLauraceaeThe Lauraceae or Laurel family comprises a group of flowering plants included in the order Laurales. The family contains about 55 genera and over 3500, perhaps as many as 4000, species world-wide, mostly from warm or tropical regions, especially Southeast Asia and South America...
- Family MonimiaceaeMonimiaceaeMonimiaceae is a family of flowering plants, which includes 150-220 species of shrubs and small trees in 18-25 genera. They are native to the southern hemisphere tropics and subtropics. The largest genus is Tambourissa, with 50 species in Madagascar, the Mascarene Islands, and the Comoros...
(Cronquist included Atherospermataceae and Siparunaceae in Monimiaceae) - Family TrimeniaceaeTrimeniaceaeTrimeniaceae is the botanical name of a family of flowering plants. Such a family has been recognized by most taxonomists, at least for the past several decades....
(AustrobaileyalesAustrobaileyalesAustrobaileyales is the botanical name for an order of flowering plants, consisting of about 100 species of woody plants, perhaps the most famous of which is the spice star anise.- In different classifications :...
)