phylogenetic nomenclature Phylogenetic nomenclature is a method of nomenclature for taxa in biology that uses phylogenetic definitions for taxon names as explained below. This contrasts with the traditional approach, in which taxon names are defined by a '' type'', which ...

, the Pentapetalae are a large group of

eudicots The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non-magnoliid dico ...

that were informally referred to as the "core eudicots" in some papers on

angiosperm 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 ...

phylogenetics In biology, phylogenetics (; from Greek language, Greek wikt:φυλή, φυλή/wikt:φῦλον, φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary his ...

.Stevens, P.F. 2006. Angiosperm Phylogeny Website, versión 7. http://www.mobot.org/mobot/research/apweb/ Access date: May 10, 2010. They comprise an extremely large and diverse group that accounting about 65% of the

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

richness of the

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 th ...

, with wide variability 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.

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...

chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...

, geographic distribution, and other attributes. Classical systematics, based solely on morphological information, was not able to recognize this group. In fact, the circumscription of the Pentapetalae as a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

is based on strong evidence obtained from DNA molecular analysis data. The Pentapetalae clade is composed of the orders

Berberidopsidales Berberidopsidales is an order of Southern Hemisphere woody flowering plants. The name is newly accepted in the APG III system of plant taxonomy. APG II system, of 2003, mentions the possibility of recognizing the order, as comprising the familie ...

—including the family Aextoxicaceae—

Caryophyllales Caryophyllales ( ) is a diverse and heterogeneous order of flowering plants that includes the cacti, carnations, amaranths, ice plants, beets, and many carnivorous plants. Many members are succulent, having fleshy stems or leaves. The betalai ...

Santalales The Santalales are an order of flowering plants with a cosmopolitan distribution, but heavily concentrated in tropical and subtropical regions. It derives its name from its type genus ''Santalum'' (sandalwood). Mistletoe is the common name for a ...

and

Saxifragales The Saxifragales (saxifrages) are an order of flowering plants (Angiosperms). They are an extremely diverse group of plants which include trees, shrubs, perennial herbs, succulent and aquatic plants. The degree of diversity in terms of vege ...

, the families

Dilleniaceae Dilleniaceae is a family of flowering plants with 11 genera and about 430 known species. Such a family has been universally recognized by taxonomists. It is known to gardeners for the genus ''Hibbertia'', which contains many commercially valuabl ...

and

Vitaceae The Vitaceae are a family of flowering plants, with 14 genera and around 910 known species, including common plants such as grapevines (''Vitis'' spp.) and Virginia creeper (''Parthenocissus quinquefolia''). The family name is derived from the ge ...

and all members of the clades

Asteridae ''Asteridae'' is an obsolete botanical name at the rank of subclass. Composition of the subclass has also varied; however, by definition it always includes the family Asteraceae (Compositae). In the modern APG IV system of classification, asterid ...

and

Rosidae Under the International Code of Nomenclature for algae, fungi, and plants (ICN), Rosidae is a botanical name at the rank of subclass. Circumscription of the subclass will vary with the taxonomic system being used; the only requirement being tha ...

Phylogenetic analyses In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

of complete

chloroplast genome 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 Cel ...

sequences have provided a reliable outline of the relationships among the major Pentapetalae lineages and also provide a framework for investigating the evolutionary processes that generated a large proportion of the diversity of extant angiosperms. In light of these phylogenetic results, the current challenge for scientists in this area of

botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek w ...

is to identify the characters that are unique to the superasterid and superrosid clades and those that arose in parallel in both, and then to explore their

evolutionary Evolution is change in the heredity, heritable Phenotypic trait, characteristics of biological populations over successive generations. These characteristics are the Gene expression, expressions of genes, which are passed on from parent to ...

implications.

Description

As the name of the clade suggests, the Pentapetalae have a characteristic type of

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

made up of

whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...

of five pieces each. The

perianth The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower, and structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepals when ...

is formed by a

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

and a

corona Corona (from the Latin for 'crown') most commonly refers to: * Stellar corona, the outer atmosphere of the Sun or another star * Corona (beer), a Mexican beer * Corona, informal term for the coronavirus SARS-CoV-2, which causes the COVID-19 di ...

perfectly differentiated. The sepals are innervated by three or more

vascular bundles A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in the stem, which exists in two forms: xylem and phloem. Both these tissues are present in a vascular bundle, which in addition will includ ...

—called

leaf scars A leaf scar is the mark left by a leaf after it falls off the twig. It marks the site where the petiole attached to the stem. A leaf scar is typically found below a branch as branches come from axillary buds located above leaf scars. Formation Le ...

— originating in the vascular system of the petiole, while the

petals Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corolla''. Petals are usually ...

have only one trace. The

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

usually has twice as many pieces as the calyx and corona, which are arranged in two whorls. When the number of stamens is greater than twice the number of pieces of the perianth, they are arranged in fascicles or in a centrifugal spiral. Arabis_voch1-4

Pollen grains Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

in the Pentapetalae are characteristically tricolpate. This type of pollen grain has three or more pores within grooves called "colpos". In contrast, most other

spermatophytes A spermatophyte (; ), also known as phanerogam (taxon Phanerogamae) or phaenogam (taxon Phaenogamae), is any plant that produces seeds, hence the alternative name seed plant. Spermatophytes are a subset of the embryophytes or land plants. They inc ...

—that is,

gymnosperms The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, ''Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμνό� ...

monocots Monocotyledons (), commonly referred to as monocots, (Lilianae ''sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of t ...

and paleodicots— have monoculcate pollen, with a single pore located in a groove called a "sulcus". The

gynoecium Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' ...

of Pentapetalae plants is usually composed of five

carpels Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' ...

joined together, although gynoeciums formed by three carpels are also quite common. In cases where the gynoecium is composed of only two carpels, they overlap. In general, they present "compitum", a region of the

style Style is a manner of doing or presenting things and may refer to: * Architectural style, the features that make a building or structure historically identifiable * Design, the process of creating something * Fashion, a prevailing mode of clothing ...

where the stylar canals of the different carpels are united in a single cavity and in which the pollen tubes can change direction of growth from one carpel to another. The

ovules In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the fe ...

are usually of axillary placentation. The

pistil Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' ...

, finally, commonly terminates in a style and a stigma that is not decurrent. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

is dry and dehiscent, when it is a capsule it shows loculicidal dehiscence. Regarding the interaction between

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

and pistil, pentapetalous plants have a gametophytic incompatibility system based on the RNAase system. Another anatomical characteristic of Pentapetalae is the presence of a closed root apical meristem. From the

phytochemical Phytochemicals are chemical compounds produced by plants, generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals. The name comes . Some phytochemicals have been used as poisons ...

point of view, this group of plants present cyanogenesis —that is, they biosynthesize cyanogenetic glycosides that by hydrolysis originate

cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...

— through the

metabolic pathway In biochemistry, a metabolic pathway is a linked series of chemical reactions occurring within a cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical reac ...

of branched

amino acids Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

, such as

leucine Leucine (symbol Leu or L) is an essential amino acid that is used in the biosynthesis of proteins. Leucine is an α-amino acid, meaning it contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α- ca ...

isoleucine Isoleucine (symbol Ile or I) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form under biological conditions), an α-carboxylic acid group (which is in the deprot ...

and

valine Valine (symbol Val or V) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α- carboxylic acid group (which is in the deprotonat ...

Diversity

Dilleniales

Dilleniales The Dilleniales are an order of flowering plants, potentially containing one family, Dilleniaceae. The APG III system of 2009, like the earlier APG II system of 2003, left the Dilleniaceae unplaced as to order, while noting that the name Dillenia ...

are recognized by their

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

with usually strong and parallel secondary

veins Veins are blood vessels in 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 the pulmonary and umbilical veins, both of which carry oxygenated b ...

that go straight to the teeth; being common the tertiary scalariform venation. The leaf lamina is usually rough. Also, the leaves tend to elongate when still rolled. The

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...

is usually vivid brown. The peduncles are jointed near the apex and persist after the flower falls off; the flowers are usually conspicuous, with ruffled

and numerous

stamens The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

that are reflexed in the bud, usually having porous

anthers The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

. The

fruits In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particula ...

are small follicles containing

seeds A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm pl ...

with

aril An aril (pronounced ), also called an arillus, is a specialized outgrowth from a seed that partly or completely covers the seed. An arillode or false aril is sometimes distinguished: whereas an aril grows from the attachment point of the see ...

, the calyx is persistent, sometimes acrescent, and the filaments are also persistent.

Berberidopsidales

is an order formally accepted only in the most recent phylogenetic classifications of angiosperms, comprising two small families, Aextoxicaceae and Berberidopsidaceae, which together include only three genera and four species distributed in

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

and eastern

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. The distinctive characters of the order are largely related to its anatomy, such as the presence of crystals —especially

drusen Drusen, from the German word for ''node'' or ''geode'' (singular, "Druse"), are tiny yellow or white accumulations of extracellular material that build up between Bruch's membrane and the retinal pigment epithelium of the eye. The presence of a f ...

— in the leaves and petioles, the

of the petiole form a ring and the

stoma In botany, a stoma (from Greek ''στόμα'', "mouth", plural "stomata"), also called a stomate (plural "stomates"), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange. The pore is bor ...

of the

leaf epidermis The epidermis (from the Greek ''ἐπιδερμίς'', meaning "over-skin") is a single layer of cells that covers the leaves, flowers, roots and stems of plants. It forms a boundary between the plant and the external environment. The epidermis ...

are of a particular type called " cyclocytic". The

androecium The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

has

with rigid filament and the

present endotesta. The flowers of '' Berberidopsis corallina'' do not differ in

sepals A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

and

, but exhibit a gradual transition from small outer

tepals A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

to larger, brightly colored inner tepals. The androcecium consists of a ring of stamens and there are three

with parietal

placentation Placentation refers to the formation, type and structure, or arrangement of the placenta. The function of placentation is to transfer nutrients, respiratory gases, and water from maternal tissue to a growing embryo, and in some instances to remove ...

. In contrast, ''

Aextoxicon ''Aextoxicon punctatum'', the sole species of genus ''Aextoxicon'' and family Aextoxicaceae, is a dioecious tree native to southern Chile and Argentina. Commonly known as the ''olivillo'' or ''aceitunillo'', it is a large evergreen tree native t ...

'' has unisexual and pentamerous flowers. Male flowers have a distinct calyx and

and a haplostomous androcecium. Female flowers have the same type of perianth, but the number of pieces is more variable. Given these differences between the two genera belonging to the same family, it has been suggested that the floral development of Berberidopsidales is a "link" in the

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

of the Gunneridae flower, and that the floral morphology of ''

'', with features such as the highly variable number of sepals and spirally arranged petals, is also compatible with this hypothesis. However, the position of the Berberidopsidales in the phylogenetic tree is not congruent with it.

Santalales

Santalum_album_(Chandan)_in_Hyderabad,_AP_W2_IMG_0023

The order

, with its approximately 160 genera and 2,200 species distributed worldwide, is a monophyletic group that has long occupied an unresolved position at the base of the Gunneridae. Recently, phylogenetic studies based on molecular data from the complete chloroplast genome indicate a position of Santalales at the base of the Asterids. Santalales is ecologically diverse and includes free-living plants, such as '' Erythropalum'', as well as (hemi)parasites. Among the latter are species that parasitize stems or shoots, such as the mistletoes of the genus '' Misodendrum'', and

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the sur ...

parasites, including the well-known and economically important sandalwood tree (''

Santalum album ''Santalum album'', or Indian sandalwood, is a small tropical tree, and the traditional source of sandalwood oil. It is native to southern India and Southeast Asia. It is considered sacred in some religions like Hinduism, and some cultures place ...

''), whose aromatic wood is a component of many perfumes. The

APG III APG is an abbreviation with several different meanings: * Aberdeen Proving Ground, a United States Army installation in Aberdeen, Maryland, also ** Phillips Army Airfield, the airfield of the above, from its IATA airport code * Aboriginal Provisiona ...

classification system recognized seven families in Santalales:

Balanophoraceae The Balanophoraceae are a subtropical to tropical family of obligate parasitic flowering plants, notable for their unusual development and formerly obscure affinities. In the broadest circumscription, the family consists of 16 genera. Alternativ ...

Misodendraceae ''Misodendrum'' is a genus of hemiparasites which grow as mistletoes on various species of ''Nothofagus''. Its species are all restricted to South America. The name of the genus is incorrectly spelt in a number of ways, including ''Misodendron'' ...

Opiliaceae Opiliaceae is a family of flowering plants comprising 11 genera and 33 known species. It consists of tropical woody plants. Several genera contain parasitic species. The biggest genus, in number of species and in stature of the individual plant ...

Schoepfiaceae Schoepfiaceae is a family of flowering plants recognized in the APG III system of 2009. The family was previously only recognized by few taxonomists; the plants in question usually being assigned to family Olacaceae and Santalaceae. The genus '' ...

Loranthaceae Loranthaceae, commonly known as the showy mistletoes, is a family of flowering plants. It consists of about 75 genera and 1,000 species of woody plants, many of them hemiparasites. The three terrestrial species are ''Nuytsia floribunda'' (the W ...

Santalaceae The Santalaceae, sandalwoods, are a widely distributed family of flowering plants (including small trees, shrubs, perennial herbs, and epiphytic climbersHewson & George t al.br>''Santalaceae'' taxonomy, 1984, pp. 191-194.) which, like other membe ...

(including

Viscaceae Viscaceae is a taxonomic family name of flowering plants. In this circumscription, the family includes the several genera of mistletoes. This family name is currently being studied and under review as in past decades, several systems of plant taxon ...

), and

Olacaceae Olacaceae is a family of flowering plants in the order Santalales. They are woody plants, native throughout the tropical regions of the world. , the circumscription of the family varies; some sources maintain a broad family, others split it into ...

. In 2010, however, new molecular data have made it possible to revise that conclusion, so that Aptandraceae,

, Coulaceae, Erythropalaceae,

, Octonemaceae,

, Strombosiaceae, and Ximeniaceae are now recognized.

Rosids

The

rosids 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 classificatio ...

are a large group of eudicotyledons containing approximately 70 000 species, more than a quarter of the total number of angiosperm species. It has been subdivided into some 16 to 20 orders, depending on the circumscription and classification adopted. These orders, in turn, comprise about 140

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...

. Together with the asterids, they constitute the two largest groups of eudicotyledons. The rosids share a few morphological characteristics that distinguish them from other groups, such as the presence of

nectaries Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...

in the floral receptacle, the long embryo and the distinctive mucilaginous cells. At the molecular level, the rossids are characterized by the loss of function of the

chloroplast A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in ...

''infA''

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

and the absence of the ''coxII.i3''

intron An intron is any nucleotide sequence within a gene that is not expressed or operative in the final RNA product. The word ''intron'' is derived from the term ''intragenic region'', i.e. a region inside a gene."The notion of the cistron .e., gene. ...

in the

mitochondrion A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used ...

Asterids

The

asterids In the APG IV system (2016) for the classification of flowering plants, the name asterids denotes a clade (a monophyletic group). Asterids is the largest group of flowering plants, with more than 80,000 species, about a third of the total floweri ...

are a large group of eudicotyledons that includes approximately 80 000 species, grouped in 13 orders and more than a hundred

, and between a third and a quarter of the total number of

species. Together with the

, they constitute the two largest groups of eudicotyledons. They represent the most apotypic clade of the angiosperms, or, as it is inappropriately called, "most evolved". The group most likely originated in the

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...

, about 50 million years ago, and its success is related to its adaptation to insect pollinators. Four of the largest families of angiosperms belong to this

: the

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

, the

Rubiaceae The Rubiaceae are a family of flowering plants, commonly known as the coffee, madder, or bedstraw family. It consists of terrestrial trees, shrubs, lianas, or herbs that are recognizable by simple, opposite leaves with interpetiolar stipules ...

, the

Lamiaceae The Lamiaceae ( ) or Labiatae are a family of flowering plants commonly known as the mint, deadnettle or sage family. Many of the plants are aromatic in all parts and include widely used culinary herbs like basil, mint, rosemary, sage, savory ...

and the

Apocynaceae Apocynaceae (from ''Apocynum'', Greek for "dog-away") is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison Members of the ...

. The plants belonging to this clade are characterized by being herbaceous, with

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...

zygomorphic Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts. Uncommonly, flowers may have no axis of symmetry at all, typically because their parts are spirall ...

flowers A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

—that is, they admit only one plane of symmetry— that are pollinated by insects. In addition, the

are arranged in a circle and the

of the

are joined together forming a tube. The

is formed by two welded

. The flowers are often arranged in tight

inflorescences An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

, such as the

ears An ear is the organ that enables hearing and, in mammals, body balance using the vestibular system. In mammals, the ear is usually described as having three parts—the outer ear, the middle ear and the inner ear. The outer ear consists o ...

of the

labiatae The Lamiaceae ( ) or Labiatae are a family of flowering plants commonly known as the mint, deadnettle or sage family. Many of the plants are aromatic in all parts and include widely used culinary herbs like basil, mint, rosemary, sage, savory ...

and

plantaginaceae Plantaginaceae, the plantain family, is a large, diverse family of flowering plants in the order Lamiales that includes common flowers such as snapdragon and foxglove. It is unrelated to the banana-like fruit also called "plantain." In older cl ...

or the capitula (heads) of the

compositae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

Evolution and phylogeny

The age of this clade has been estimated at 113 to 116 million years. The oldest macrofossils of eudicots, which unfortunately cannot be attributed to any extant group, belong to the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

, just 96-94 million years old. Analyses of complete chloroplast genome sequences allowed us to resolve the relationships among the major Pentapetalae clades. Immediately after diverging from the

Gunnerales The Gunnerales are an order of flowering plants. In the APG III system (2009) and APG IV system (2016) it contains two genera: ''Gunnera'' (in family Gunneraceae) and ''Myrothamnus'' (in family Myrothamnaceae). In the Cronquist system (1981), t ...

, the Pentapetalae diverged into three major subclades: (i) the Dileniaceae, (ii) the "superrosid" clade including the

and

Rosids 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 classificatio ...

, and (iii) the "superasterid" clade composed of the

and

Asterids In the APG IV system (2016) for the classification of flowering plants, the name asterids denotes a clade (a monophyletic group). Asterids is the largest group of flowering plants, with more than 80,000 species, about a third of the total floweri ...

. The close relationship demonstrated at the molecular scale between Saxifragales, Vitaceae and rosids is congruent with their morphological affinities. In fact, these clades form the so-called "core of the rosids" in the Cronquist and

Takhtajan Armen Leonovich Takhtajan or Takhtajian ( hy, Արմեն Լևոնի Թախտաջյան; russian: Армен Леонович Тахтаджян; surname also transliterated Takhtadjan, Takhtadzhi︠a︡n or Takhtadzhian, pronounced takh-tuh-JA ...

classification systems. They all have an androcecium with jointed

, leaves with

stipules In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...

, the

endosperm The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the embryo and ...

with nuclear formation, and a

micropyle Micropyle may refer to: * Micropyle (botany) In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (o ...

that forms from the outer integument or both integuments. Several putative

synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...

may also characterize the superrosid clade. Thus, the "psyllulate" pollen or with a granular structure of the exine, the presence of

sclereids Sclereids are a reduced form of sclerenchyma cells with highly thickened, lignified cellular walls that form small bundles of durable layers of tissue in most plants.Evert, Ray F; Eichhorn, Susan E. Esau's Plant Anatomy: Meristems, Cells, and Ti ...

in the leaves, the isomerism of the androcecium and the fused carpels unite the santalales, the caryophyllales and the asterids. Likewise, leaves without stipules may be another synapomorphic character, although Berberidopsidaceae have stipules and Aextoxicaceae lack them; thus, the ancestral status of Berberidopsidales and asterids is still unclear. The initial divergence between the Dilleniales, superrosids and superasterids must have occurred very quickly, within a period of one million years after the initial separation of the Pentapetalae from the Gunnerales. Likewise, the superrosids and superasterids show an early and very rapid divergence since the lineages that led to the Vitaceae, Saxifragales, and rosids arose within a period of only five million years, as did those that led to the appearance of the Berberidopsidales, Caryophyllales, and asterids. The following

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

summarizes the phylogenetic relationships within the Pentapetalae clade and this clade. {{clade , style=line-height:1em; , label1=eudicots , 1={{cladex , label1=basal eudicots , 1=(paraphyletic group:

Ranunculales Ranunculales is an order of flowering plants. Of necessity it contains the family Ranunculaceae, the buttercup family, because the name of the order is based on the name of a genus in that family. Ranunculales belongs to a paraphyletic group kno ...

Proteales Proteales is an order of flowering plants consisting of three (or four) families. The Proteales have been recognized by almost all taxonomists. The representatives of the Proteales are very different from each other. The order contains plants ...

Trochodendrales Trochodendraceae is the only family of flowering plants in the order Trochodendrales. It comprises two extant genera, each with a single species along with up to five additional extinct genera and a number of extinct species. The living speci ...

Buxales The Buxales are a small order of eudicot flowering plants, recognized by the APG IV system of 2016. The order includes the family Buxaceae; the families Didymelaceae and Haptanthaceae may also be recognized or may be included in the Buxaceae. Man ...

), state1=double , label2=core eudicots , 2={{clade , 1=

, label2=Pentapetalae , 2={{clade , 1=

, 2={{clade , label1=

superrosids The superrosids are members of a large clade (monophyletic group) of flowering plants, containing more than 88,000 species, and thus more than a quarter of all angiosperms. The clade is divided into 18 orders as defined in APG IV system. These o ...

, 1={{clade , 1=

, label2=

, 2={{clade , 1=

Vitales The Vitaceae are a family of flowering plants, with 14 genera and around 910 known species, including common plants such as grapevines (''Vitis'' spp.) and Virginia creeper (''Parthenocissus quinquefolia''). The family name is derived from the ge ...

, label2=

eurosids The rosids are members of a large clade (monophyly, 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 Order (biology), orders, depending upon Circu ...

, 2={{clade , 1=

fabids 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 classificatio ...

(8 orders) , 2=

malvids 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 classificatio ...

(8 orders) , label2= superasterids , 2={{clade , 1=

, 2={{clade , 1=

, label2=

, 2={{clade , 1=

Cornales The Cornales are an order of flowering plants, early diverging among the asterids, containing about 600 species. Plants within the Cornales usually have four-parted flowers, drupaceous fruits, and inferior to half-inferior gynoecia topped with d ...

, 2={{clade , 1=

Ericales The Ericales are a large and diverse order of dicotyledons. Species in this order have considerable commercial importance including for Camellia sinensis, tea, persimmon, blueberry, kiwifruit, Brazil nuts, Argania, argan, and azalea. The order i ...

, label2=

euasterids In the APG IV system (2016) for the classification of flowering plants, the name asterids denotes a clade (a monophyletic group). Asterids is the largest group of flowering plants, with more than 80,000 species, about a third of the total floweri ...

, 2={{clade , 1=

campanulids In the APG IV system (2016) for the classification of flowering plants, the name asterids denotes a clade (a monophyletic group). Asterids is the largest group of flowering plants, with more than 80,000 species, about a third of the total floweri ...

(7 orders) , 2=

lamiids In the APG IV system (2016) for the classification of flowering plants, the name asterids denotes a clade (a monophyletic group). Asterids is the largest group of flowering plants, with more than 80,000 species, about a third of the total floweri ...

(8 orders) The names lamiids (for euasterids I) and campanulids (for euasterids II) were suggested by Bremer ''et al''. (2002) and later suggested fabiids (for eurosids I) and malvids (for eurosids II).

References

Eudicots Core eudicots Plant unranked clades