The Myrtales are an order of
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
s placed as a sister to the
eurosids II
The rosids are members of a large clade ( monophyletic group) of flowering plants, containing about 70,000 species, more than a quarter of all angiosperms.
The clade is divided into 16 to 20 orders, depending upon circumscription and classific ...
clade as of the publishing of the ''Eucalyptus grandis'' genome in June 2014.
The
APG III system of classification for
angiosperms
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants ...
still places it within the eurosids. This finding is corroborated by the placement of the Myrtales in the Malvid clade by the One Thousand Plant Transcriptomes Initiative. The following families are included as of APGIII:
*
Alzateaceae S. A. Graham
*
Combretaceae
The Combretaceae, often called the white mangrove family, are a family of flowering plants in the order Myrtales. The family includes about 530 species of trees, shrubs, and lianas in ca 10 genera. The family includes the leadwood tree, ''Combret ...
R. Br. (
leadwood family)
*
Crypteroniaceae A. DC.
*
Lythraceae J. St.-Hil. (
loosestrife and
pomegranate
The pomegranate (''Punica granatum'') is a fruit-bearing deciduous shrub in the family Lythraceae, subfamily Punicoideae, that grows between tall.
The pomegranate was originally described throughout the Mediterranean Basin, Mediterranean re ...
family)
*
Melastomataceae
Melastomataceae is a family of dicotyledonous flowering plants found mostly in the tropics (two-thirds of the genera are from the New World tropics) comprising c. 175 genera and c. 5115 known species. Melastomes are annual or perennial herbs, s ...
Juss. (including
Memecylaceae
Memecylaceae DC. was a family of flowering plants. The family included about 430 species of trees and shrubs in seven genera. Memecylaceae are widespread in the tropics. The family has now been included within the Melastomataceae under the APG II ...
DC.)
*
Myrtaceae Juss. (myrtle family; including
Heteropyxidaceae
''Heteropyxis'' is a genus which includes three species of small evergreen trees. It was previously placed along in family Heteropyxidaceae, but is now placed basally within Myrtaceae. The species of ''Heteropyxis'' are native to southern Africa. ...
Engl. & Gilg,
Psiloxylaceae
''Psiloxylon mauritianum'' (known locally as "bois bigaignon") is a species of flowering plant, the sole species of the genus ''Psiloxylon''. It is endemic to the Mascarene Islands (Mauritius and Réunion) in the Indian Ocean.
It is a white-ba ...
Croizat)
*
Onagraceae
The Onagraceae are a family of flowering plants known as the willowherb family or evening primrose family. They include about 650 species of herbs, shrubs, and trees[evening primrose
''Oenothera'' is a genus of about 145 species of herbaceous flowering plants native to the Americas. It is the type genus of the family Onagraceae. Common names include evening primrose, suncups, and sundrops. They are not closely related to ...]
and
Fuchsia
''Fuchsia'' () is a genus of flowering plants that consists mostly of shrubs or small trees. The first to be scientifically described, ''Fuchsia triphylla'', was discovered on the Caribbean island of Hispaniola (Haiti and the Dominican Republic) ...
family)
*
Penaeaceae
The Penaeaceae are a family of evergreen, leathery-leaved shrubs and small trees, native to South Africa. The family has 29 species in 9 genera.Stevens, P. F. (2001 onwards)Penaeaceae. Sweet ex Guill. (including
Oliniaceae Arn.,
Rhynchocalycaceae L. A. S. Johnson & B. G. Briggs)
*
Vochysiaceae A. St.-Hil.
The
Cronquist system
The Cronquist system is a taxonomic classification system of flowering plants. It was developed by Arthur Cronquist in a series of monographs and texts, including ''The Evolution and Classification of Flowering Plants'' (1968; 2nd edition, 1988) ...
gives essentially the same composition, except the
Vochysiaceae are removed to the order
Polygalales
The Fabales are an order of flowering plants included in the rosid group of the eudicots in the Angiosperm Phylogeny Group II classification system. In the APG II circumscription, this order includes the families Fabaceae or legumes (including ...
, and the
Thymelaeaceae
The Thymelaeaceae are a cosmopolitan family of flowering plants composed of 50 genera (listed below) and 898 species.Zachary S. Rogers (2009 onwards)A World Checklist of Thymelaeaceae (version 1) Missouri Botanical Garden Website, St. Louis. It ...
are included. The families
Sonneratiaceae,
Trapaceae
The water caltrop is any of three extant species of the genus ''Trapa'': ''Trapa natans'', ''Trapa bicornis'' and the endangered ''Trapa rossica''. It is also known as buffalo nut, bat nut, devil pod, ling gok ( Chinese: 菱角), ling nut, lin ko ...
, and
Punicaceae are removed from the Lythraceae. In the classification system of
Dahlgren the Myrtales were in the
superorder Myrtiflorae (also called Myrtanae). The APGIII system agrees with the older Cronquist circumscriptions of treating Psiloxylaceae and Heteropyxidaceae within Myrtaceae, and Memecyclaceae within Melastomataceae.
Ellagitannin
The ellagitannins are a diverse class of hydrolyzable tannins, a type of polyphenol formed primarily from the oxidative linkage of galloyl groups in 1,2,3,4,6-pentagalloyl glucose. Ellagitannins differ from gallotannins, in that their galloyl ...
s are reported in dicotyledoneous angiosperms, and notably in species in the order Myrtales.
Origins
Myrtales is dated to have begun 89–99 million years ago (mya) in
Australasia
Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologi ...
. There is some contention as to that date however, which was obtained using
nuclear DNA
Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. I ...
. When looking at
chloroplast DNA
Chloroplast DNA (cpDNA) is the DNA located in chloroplasts, which are photosynthetic organelles located within the cells of some eukaryotic organisms. Chloroplasts, like other types of plastid, contain a genome separate from that in the cell n ...
, the myrtales ancestor is instead considered to have evolved in the mid-Cretaceous period (100mya) in Southeast Africa, rather than in Australasia.
Although the APG system classifies myrtales as within the eurosids, the recently published genome of ''Eucalyptus grandis'' places the order myrtales as a sister to the eurosids rather than inside them. The discrepancy is thought to have arisen due to the difference between using numerous taxa versus using various genes for constructing a phylogeny.
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References
Further reading
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External links
{{Authority control
Angiosperm orders
Flora of Australasia