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The
family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typically subject to the same Politic ...
Asteraceae, alternatively Compositae, consists of over 32,000 known species of
flowering plant Flowering plants include multiple members of the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greec ...

flowering plant
s in over 1,900 genera within the
order Order or ORDER or Orders may refer to: * Orderliness Orderliness is associated with other qualities such as cleanliness Cleanliness is both the abstract state of being clean and free from germs, dirt, trash, or waste, and the habit of achieving a ...
Asterales Asterales is an Order (biology), order of dicotyledonous flowering plants that includes the large Family (biology), family Asteraceae (or Compositae) known for composite flowers made of Floret#floret, florets, and ten families related to the As ...
. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae were first described in 1740. The number of species in Asteraceae is rivaled only by the
Orchidaceae Orchidaceae ( ), common name, commonly called the orchid family, is a diverse and widespread family (biology), family of flowering plants, with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two lar ...

Orchidaceae
, and which is the larger family is unclear as the quantity of
extant Extant is the opposite of the word extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the endling, last individual o ...
species in each family is unknown. Most species of Asteraceae are
annual Annual may refer to: *Annual publication, periodical publications appearing regularly once per year **Yearbook **Literary annual *Annual plant *Annual report *Annual giving *Annual, Morocco, a settlement in northeastern Morocco *Annuals (band), a ...
,
biennial Biennial means (an event) lasting for two years or occurring every two years. The related term biennium is used in reference to a period of two years. In particular, it can refer to: * Biennial plant, a plant which blooms in its second year and th ...
, or
perennial A perennial plant or simply perennial is a plant Plants are predominantly photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and incl ...
herbaceous plants, but there are also shrubs, vines, and trees. The family has a widespread distribution, from subpolar to tropical regions in a wide variety of habitats. Most occur in hot desert and cold or hot semi-desert climates, and they are found on every continent but Antarctica. The primary common characteristic is the existence of sometimes hundreds of tiny individual
florets This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of le ...
which are held together by protective
involucre ''). All the "leaves" in this image are bracts. In botany Botany, also called , plant biology or phytology, is the science Science (from the Latin word ''scientia'', meaning "knowledge") is a systematic enterprise that Scientific metho ...
s in
flower head A pseudanthium (Greek for "false flower") is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower head, composite ...

flower head
s, or more technically, ''capitula''. The oldest known fossils are pollen grains from the
Late Cretaceous The Late Cretaceous (100.5–66 Year#SI prefix multipliers, Ma) is the younger of two epoch (geology), epochs into which the Cretaceous geological period, Period is divided in the geologic time scale. Stratum, Rock strata from this epoch form the ...
(
Campanian The Campanian is the fifth of six age (geology), ages of the Late Cretaceous epoch (geology), epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stage (stratigraphy) ...
to
Maastrichtian The Maastrichtian () is, in the ICS ICS may refer to: Computing * Image Cytometry Standard, a digital multidimensional image file format used in life sciences microscopy * Industrial control system, computer systems and networks used to contr ...
) of Antarctica, dated to ∼76–66
million years (myr)
million years (myr)
. It is estimated that the
crown group In phylogenetics In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Physiology, ph ...
of Asteraceae evolved at least 85.9 myr (Late Cretaceous,
Santonian The Santonian is an age (geology), age in the geologic timescale or a chronostratigraphy, chronostratigraphic stage (stratigraphy), stage. It is a subdivision of the Late Cretaceous epoch (geology), epoch or Upper Cretaceous series (stratigraphy), ...
) with a stem node age of 88–89 myr (Late Cretaceous,
Coniacian The Coniacian is an age or stage Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a week ...
). Asteraceae is an economically important family, providing food staples, garden plants, and herbal medicines. Species outside of their native ranges can be considered
weedy
weedy
or
invasive Invasive may refer to: *Invasive (medical) procedure *Invasive species *Invasive observation, especially in reference to surveillance *Invasively progressive spread of disease from one organ in the body to another, especially in reference to cancer, ...
.


Description

Members of the Asteraceae are mostly
herbaceous plants Herbaceous plants are vascular plants that have no persistent wood, woody stems above ground, including many perennial plant, perennials, and nearly all Annual plant, annuals and Biennial plant, biennials. Definitions of "herb" and "herbaceous" ...
, but some shrubs, vines, and trees (such as ''
Lachanodes arborea ''Lachanodes arborea'' (she cabbage tree) is a small tree in the family Asteraceae. It is an endangered endemic of the island of Saint Helena in the South Atlantic Ocean. See also *Flora of Saint Helena *Pladaroxylon leucadendron, He cabbage tre ...
'') do exist. Asteraceae species are generally easy to distinguish from other plants because of their unique
inflorescence An inflorescence is a group or cluster of flower A flower, sometimes known as a bloom or blossom Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fruit tree, trees (genus ''Prunus'') and of some ...
and other shared characteristics. However, determining genera and species of some groups such as ''
Hieracium ''Hieracium'' , known by the common name hawkweed and classically as (from ancient Greek ιεράξ, 'hawk'), is a genus of the sunflower (''Helianthus'') Family (biology), family Asteraceae), and closely related to dandelion (''Taraxacum''), ...

Hieracium
'' is notoriously difficult (see "
damned yellow composite A damned or damn yellow composite (DYC) is any of the numerous species of composite flowers (family Asteraceae) that have yellow flowers and can be difficult to tell apart in the field. page 230 It is a jocular term, and sometimes reserved for tho ...
" for example).


Roots

Members of the family Asteraceae generally produce
taproot A taproot is a large, central, and dominant root In vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpip ...
s, but sometimes they possess fibrous root systems. Some species have underground stems in the form of caudices or
rhizome In 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 A ...

rhizome
s. These can be fleshy or woody depending on the species.


Stems

Stems are herbaceous, aerial, branched, and cylindrical with glandular hairs, generally erect, but can be prostrate to ascending. The stems can contain secretory canals with
resin In polymer chemistry Polymer chemistry is a sub-discipline of chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, stru ...

resin
, or
latex Latex is a stable dispersion (emulsion An emulsion is a mixture of two or more liquids that are normally Miscibility, immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class o ...

latex
which is particularly common among the
Cichorioideae The Cichorioideae are a subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family (biology), family but more inclusive than genus. Standard nomenclature rules end s ...
.


Leaves

Leaves can be
alternate ''AlterNative: An International Journal of Indigenous Peoples'' (formerly ''AlterNative: An International Journal of Indigenous Scholarship'') is a quarterly peer-reviewed Peer review is the evaluation of work by one or more people with simi ...
, opposite, or whorled. They may be
simple Simple or SIMPLE may refer to: * Simplicity, the state or quality of being simple Arts and entertainment * ''Simple'' (album), by Andy Yorke, 2008, and its title track * "Simple" (Florida Georgia Line song), 2018 * "Simple", a song by Johnn ...
, but are often deeply
lobed The following is a defined list of terms which are used to describe leaf plant morphology, morphology in the description and taxonomy (biology), taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leafl ...
or otherwise incised, often conduplicate or revolute. The margins also can be
entire *In philately, see Cover (philately), Cover *In mathematics, see Entire function *In animal fancy and animal husbandry, entire (animal), entire indicates that an animal has not been desexed, that is, spayed or neutered *In botany, an edge (such as o ...
or toothed. Resin or latex also can be present in the leaves.


Inflorescences

Nearly all Asteraceae bear their flowers in dense flower heads called ''capitula''. They are surrounded by involucral bracts, and when viewed from a distance, each capitulum may appear to be a single flower. Enlarged outer (peripheral) flowers in the capitulum may resemble petals, and the involucral bracts may look like a calyx.


Floral heads

In plants of the family Asteraceae, what appears to be a single flower is actually a cluster of much smaller flowers. The overall appearance of the cluster, as a single flower, functions in attracting
pollinators A pollinator is an animal that moves pollen Pollen is a powdery substance consisting of pollen grains which are microsporophytes of seed plants The spermatophytes (; ), also known as phanerogams (taxon Phanerogamae) or phaenogams (taxo ...
in the same way as the structure of an individual flower in some other plant families. The older family name, Compositae, comes from the fact that what appears to be a single flower is actually a ''composite'' of smaller flowers. The "petals" or "sunrays" in a sunflower head are actually individual strap-shaped flowers called ray flowers, and the "sun disk" is made of smaller circular shaped individual flowers called disc flowers. The word "aster" means "star" in Greek, referring to the appearance of some family members, as a "star" surrounded by "rays". The cluster of flowers that may appear to be a single flower, is called a ''head''. The entire head may move tracking the sun, like a "smart" solar panel, which maximizes reflectivity of the whole unit and can thereby attract more pollinators. On the outside the flower heads are small bracts that look like scales. These are called ''
phyllaries In botanical terminology, a phyllary, also known an involucral bract or tegule, is a single bract ''). All the "leaves" in this image are bracts. In botany Botany, also called , plant biology or phytology, is the science Science (from ...
'', and together they form the
involucre ''). All the "leaves" in this image are bracts. In botany Botany, also called , plant biology or phytology, is the science Science (from the Latin word ''scientia'', meaning "knowledge") is a systematic enterprise that Scientific metho ...
that protects the individual flowers in the head before they open. The individual heads have the smaller individual flowers arranged on a round or dome-like structure called the ''receptacle''. The flowers mature first at the outside, moving toward the center, with the youngest in the middle. The individual flowers in a head have 5 fused petals (rarely 4), but instead of sepals, have threadlike, hairy, or bristly structures called '' pappus'', which surround the fruit and can stick to animal fur or be lifted by wind, aiding in seed dispersal. The whitish fluffy head of a dandelion, commonly blown on by children, is made of the pappus, with tiny seeds attached at the ends, whereby the pappus provides a parachute like structure to help the seed be carried away in the wind. A ''ray flower'' is a 3-tipped (3-lobed), strap-shaped, individual flower in the head of some members of the family Asteraceae. Sometimes a ray flower is 2-tipped (2-lobed). The
corolla Corolla may refer to: *Corolla (botany) upright=1.4, Diagram showing the parts of a mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals) The perianth (perigonium, perigon or perigone in monocots) is ...

corolla
of the ray flower may have 2 tiny teeth opposite the 3-lobed strap, or tongue, indicating evolution by fusion from an originally 5-part corolla. Sometimes, the 3:2 arrangement is reversed, with 2 tips on the tongue, and 0 or 3 tiny teeth opposite the tongue. A ''ligulate flower'' is a 5-tipped, strap-shaped, individual flower in the heads of other members. A ''ligule'' is the strap-shaped tongue of the
corolla Corolla may refer to: *Corolla (botany) upright=1.4, Diagram showing the parts of a mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals) The perianth (perigonium, perigon or perigone in monocots) is ...

corolla
of either a ray flower or of a ligulate flower. A ''disk flower'' (or ''disc flower'') is a radially symmetric (i.e., with identical shaped petals arranged in circle around the center) individual flower in the head, which is ringed by ray flowers when both are present. Sometimes ray flowers may be slightly off from radial symmetry, or weakly bilaterally symmetric, as in the case of desert pincushions ''''. A ''radiate head'' has disc flowers surrounded by ray flowers. A ''ligulate head'' has all ligulate flowers. When a sunflower family flower head has only disc flowers that are sterile, male, or have both male and female parts, it is a ''discoid head''. ''Disciform heads'' have only disc flowers, but may have two kinds (male flowers and female flowers) in one head, or may have different heads of two kinds (all male, or all female). ''Pistillate heads'' have all female flowers. ''Staminate heads'' have all male flowers. Sometimes, but rarely, the head contains only a single flower, or has a single flowered pistillate (female) head, and a multi-flowered male staminate (male) head.


Floral structures

The distinguishing characteristic of Asteraceae is their
inflorescence An inflorescence is a group or cluster of flower A flower, sometimes known as a bloom or blossom Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fruit tree, trees (genus ''Prunus'') and of some ...
, a type of specialised, composite flower head or ''
pseudanthium A pseudanthium (Greek for "false flower") is an inflorescence An inflorescence is a group or cluster of flower A flower, sometimes known as a bloom or blossom Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers ...
'', technically called a calathium or '' capitulum'', that may look superficially like a single flower. The ''capitulum'' is a contracted
raceme A raceme ( or ) or racemoid is an unbranched, indeterminate growth, indeterminate type of inflorescence bearing ''pedicellate'' flowers (flowers having short floral stalks called Pedicel (botany), pedicels) along its axis. In botany, an ''axis'' ...

raceme
composed of numerous individual sessile
flower A flower, sometimes known as a bloom or blossom Image:Cerisier du Japon Prunus serrulata.jpg, Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fruit tree, trees (genus ''Prunus'') and of some other plan ...

flower
s, called ''florets'', all sharing the same
receptacle Receptacle may refer to: Biology * Receptacle (botany), a plant anatomical part * Seminal receptacle, a sperm storage site in some insects Electrical engineering * Auxiliary car power outlet, formerly known as ''Cigarette lighter receptacle'', a ...
. A set of
bract In 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 Anci ...

bract
s forms an
involucre ''). All the "leaves" in this image are bracts. In botany Botany, also called , plant biology or phytology, is the science Science (from the Latin word ''scientia'', meaning "knowledge") is a systematic enterprise that Scientific metho ...
surrounding the base of the capitulum. These are called "phyllaries", or "involucral bracts". They may simulate the
sepal A sepal ( or ) is a part of the flower A flower, sometimes known as a bloom or blossom Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fruit tree, trees (genus ''Prunus'') and of some other p ...
s of the pseudanthium. These are mostly herbaceous but can also be brightly coloured (e.g. '''') or have a scarious (dry and membranous) texture. The phyllaries can be free or fused, and arranged in one to many rows, overlapping like the tiles of a roof (''imbricate'') or not (this variation is important in identification of tribes and genera). Each floret may be subtended by a bract, called a "palea" or "receptacular bract". These bracts are often called "
chaff Chaff (; ) is the dry, scaly protective casing of the seeds of cereal grain A cereal is any grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants known as grasses. It includes ...
". The presence or absence of these bracts, their distribution on the receptacle, and their size and shape are all important diagnostic characteristics for genera and tribes. The florets have five
petal Petals are modified leaves A leaf (plural leaves) is the principal lateral appendage of the vascular plant plant stem, stem, usually borne above ground and specialized for photosynthesis. The leaves, stem, flower and fruit together fo ...

petal
s fused at the base to form a
corolla Corolla may refer to: *Corolla (botany) upright=1.4, Diagram showing the parts of a mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals) The perianth (perigonium, perigon or perigone in monocots) is ...
tube and they may be either
actinomorphic Floral symmetry describes whether, and how, a flower A flower, sometimes known as a bloom or blossom Image:Cerisier du Japon Prunus serrulata.jpg, Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fru ...

actinomorphic
or
zygomorphic Floral symmetry describes whether, and how, a flower A flower, sometimes known as a bloom or blossom, is the reproduction, reproductive structure found in flowering plants (plants of the division Magnoliophyta, also called angiosperms). T ...
. ''Disc florets'' are usually actinomorphic, with five petal lips on the rim of the corolla tube. The petal lips may be either very short, or long, in which case they form deeply lobed petals. The latter is the only kind of floret in the Carduoideae, while the first kind is more widespread. ''Ray florets'' are always highly zygomorphic and are characterised by the presence of a ''ligule'', a strap-shaped structure on the edge of the corolla tube consisting of fused petals. In the Asteroideae and other minor subfamilies these are usually borne only on florets at the circumference of the capitulum and have a 3+2 scheme – above the fused corolla tube, three very long fused
petal Petals are modified leaves A leaf (plural leaves) is the principal lateral appendage of the vascular plant plant stem, stem, usually borne above ground and specialized for photosynthesis. The leaves, stem, flower and fruit together fo ...

petal
s form the ligule, with the other two petals being inconspicuously small. The Cichorioideae has only ray florets, with a 5+0 scheme – all five petals form the ligule. A 4+1 scheme is found in the Barnadesioideae. The tip of the ligule is often divided into teeth, each one representing a petal. Some marginal florets may have no petals at all (filiform floret). The calyx of the florets may be absent, but when present is always modified into a pappus of two or more teeth, scales or bristles and this is often involved in the dispersion of the seeds. As with the bracts, the nature of the pappus is an important diagnostic feature. There are usually five
stamen The stamen (plural The plural (sometimes abbreviated An abbreviation (from Latin ''brevis'', meaning ''short'') is a shortened form of a word or phrase, by any method. It may consist of a group of letters, or words taken from the full ve ...
s. The filaments are fused to the corolla, while the anthers are generally connate (''syngenesious'' anthers), thus forming a sort of tube around the style (''theca''). They commonly have basal and/or apical appendages. Pollen is released inside the tube and is collected around the growing style, and then, as the style elongates, is pushed out of the tube (''nüdelspritze''). The
pistil Gynoecium (; ) is most commonly used as a collective term for the parts of a flower A flower, sometimes known as a bloom or blossom Image:Cerisier du Japon Prunus serrulata.jpg, Cherry blossoms in Paris in full bloom. In botany, blossoms ...
consists of two connate
carpel Gynoecium (; ) is most commonly used as a collective term for the parts of a flower A flower, sometimes known as a bloom or blossom Image:Cerisier du Japon Prunus serrulata.jpg, Cherry blossoms in Paris in full bloom. In botany, blossoms ...
s. The
style Style is a manner of doing or presenting things and may refer to: * Architectural style An architectural style is a set of characteristics and features that make a building or other structure notable or historically identifiable. It is a sub-cla ...
has two lobes. Stigmatic tissue may be located in the interior surface or form two lateral lines. The
ovary The ovary is an organ found in the female reproductive system The female reproductive system is made up of the internal and external sex organs that function in reproduction of new offspring. In humans, the female reproductive system is im ...
is inferior and has only one
ovule In seed plant A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warner Bros. Records, Warner Bros. The band's first double album, it was released ...

ovule
, with basal
placentation In biology, placentation refers to the formation, type and structure, or arrangement of the placenta The placenta is a temporary fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in faci ...

placentation
.


Fruits and seeds

In members of the Asteraceae the fruit is
achene An achene (; Greek ἀ, ''a'', privative A privative, named from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rom ...

achene
-like, and is called a ''cypsela'' (plural ''cypselae''). Although there are two fused
carpel Gynoecium (; ) is most commonly used as a collective term for the parts of a flower A flower, sometimes known as a bloom or blossom Image:Cerisier du Japon Prunus serrulata.jpg, Cherry blossoms in Paris in full bloom. In botany, blossoms ...
s, there is only one locule, and only one
seed A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warner Bros. Records, Warner Bros. The band's first double album, it was released to generally positi ...

seed
per fruit is formed. It may sometimes be winged or spiny because the pappus, which is derived from calyx tissue often remains on the fruit (for example in
dandelion ''Taraxacum'' () is a large genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxono ...

dandelion
). In some species, however, the pappus falls off (for example in ''
Helianthus ''Helianthus'' () is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, vi ...

Helianthus
''). Cypsela
morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology) In archaeology, morphology is the study of the shape of Artifact (archaeology), artefacts and ecofacts. Morphology is a major consid ...
is often used to help determine plant relationships at the genus and species level. The mature
seed A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warner Bros. Records, Warner Bros. The band's first double album, it was released to generally positi ...

seed
s usually have little
endosperm The endosperm is a tissue produced inside the seed A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warner Bros. Records, Warner Bros. The band's fir ...
or none.


Pollen

The pollen of composites is typically echinolophate, a morphological term meaning "with elaborate systems of ridges and spines dispersed around and between the apertures."


Metabolites

In Asteraceae, the energy store is generally in the form of
inulin Inulins are a group of naturally occurring polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrate A carbohydrate () is a biomolecule , showing alpha helices, represented by ribbons. This poten was ...

inulin
rather than starch. They produce iso/
chlorogenic acid Chlorogenic acid (CGA) is the ester of caffeic acid and (−)-quinic acid, functioning as an intermediate in lignin biosynthesis. The term "chlorogenic acids" refers to a related polyphenol family of esters, including hydroxycinnamic acids (caffeic ...

chlorogenic acid
,
sesquiterpene Sesquiterpenes are a class of terpene Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plant ...
lactonesLactones are cyclic carboxylic esters, containing a 1-oxacycloalkan-2-one structure (), or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring. Lactones are formed by intramolecular esterification of the corre ...
, pentacyclic triterpene alcohols, various
alkaloid Alkaloids are a class of basic BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming language In computer science Computer science deals with the theoretical foundations of ...
s,
acetylene Acetylene (systematic nameA systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is ...

acetylene
s (cyclic, aromatic, with vinyl end groups),
tannin Tannins (or tannoids) are a class of astringent 200px, A crystal of the astringent alum An astringent (sometimes called adstringent) is a chemical that shrinks or constricts body tissue In biology Biology is the natural scie ...
s. They have
terpenoid The terpenoids, also known as isoprenoids, are a large and diverse class of naturally occurring organic chemicals , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain ca ...
essential oil An essential oil is a concentrated hydrophobic In 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 matte ...
s which never contain
iridoidImage:Iridomyrmecin.svg, Chemical structure of iridomyrmecin Iridoids are a type of monoterpenoids in the general form of cyclopentanopyran, found in a wide variety of plants and some animals. They are biosynthesis, biosynthetically derived from 8-o ...
s. Asteraceae produce
secondary metabolites Secondary metabolites, also called specialised metabolite In biochemistry Biochemistry or biological chemistry, is the study of chemical process In a scientific Science (from the Latin Latin (, or , ) is a classical language bel ...
, such as
flavonoid Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenol Polyphenols () are a large family of naturally occurring s characterized by multiples of units. They are abunda ...
s and
terpenoid The terpenoids, also known as isoprenoids, are a large and diverse class of naturally occurring organic chemicals , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain ca ...
s. Some of these molecules can inhibit protozoan
parasites Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is adaptation (biology), adapted structurally to this w ...
such as ''
Plasmodium ''Plasmodium'' is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of ''Plasmodium'' species involve development in a Hematophagy, blood-feeding insect host (biology), host which then inj ...

Plasmodium
'', ''
Trypanosoma ''Trypanosoma'' is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology Biology is the natural science that studies life and living organisms, including th ...

Trypanosoma
'', ''
Leishmania ''Leishmania'' is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viru ...
'' and parasitic intestinal worms, and thus have potential in medicine.


Taxonomy


History

Compositae, the original name for Asteraceae, were first described in 1740 by Dutch botanist . Traditionally, two subfamilies were recognised:
Asteroideae Asteroideae is a subfamily of the plant family Asteraceae. It contains about 70% of the species of the family. It is made of several Tribe (biology), tribes, including Astereae, Calenduleae, Eupatorieae, Gnaphalieae, Heliantheae, Senecioneae and ...
(or Tubuliflorae) and
Cichorioideae The Cichorioideae are a subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family (biology), family but more inclusive than genus. Standard nomenclature rules end s ...
(or Liguliflorae). The latter has been shown to be extensively
paraphyletic In taxonomy Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. The term may also refer to a specific classification scheme. Originally used only ...

paraphyletic
, and has now been divided into 12 subfamilies, but the former still stands. The study of this family is known as synantherology.


Phylogeny

The
phylogenetic tree A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree (graph theory), tree showing the evolutionary relationships among va ...

phylogenetic tree
presented below is based on Panero &
Funk Funk is a music genre A music genre is a conventional category that identifies some pieces of music as belonging to a shared tradition or set of conventions. It is to be distinguished from ''musical form'' and musical style, although in pra ...
(2002) updated in 2014, and now also includes the monotypic
Famatinanthoideae ''Famatinanthus'' is a genus in the family Asteraceae that was described in 2014 and has been assigned to its own tribe Famatinantheae and subfamily Famatinanthoideae. It contains only one known species, ''F. decussatus'', a small shrub of ½—1 ...
. The diamond (♦) denotes a very poorly supported
node In general, a node is a localized swelling (a "knot A knot is an intentional complication in cordage which may be practical or decorative, or both. Practical knots are classified by function, including hitches, bend Bend or bends may refer t ...

node
(<50% bootstrap support), the dot (•) a poorly supported node (<80%). The family includes over 32,000 currently accepted species, in over 1,900 genera (
list A ''list'' is any set of items. List or lists may also refer to: People * List (surname)List or Liste is a European surname. Notable people with the surname include: List * Friedrich List (1789–1846), German economist * Garrett List (194 ...
) in 13 subfamilies. The number of species in the family Asteraceae is rivaled only by Orchidaceae. Which is the larger family is unclear, because of the uncertainty about how many
extant Extant is the opposite of the word extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the endling, last individual o ...
species each family includes. The four subfamilies
Asteroideae Asteroideae is a subfamily of the plant family Asteraceae. It contains about 70% of the species of the family. It is made of several Tribe (biology), tribes, including Astereae, Calenduleae, Eupatorieae, Gnaphalieae, Heliantheae, Senecioneae and ...
,
Cichorioideae The Cichorioideae are a subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family (biology), family but more inclusive than genus. Standard nomenclature rules end s ...
,
Carduoideae Carduoideae is the thistle subfamily of the Asteraceae, or sunflower family, of flowering plants. It comprises a number of tribes in various circumscriptions of the family, in addition to the Cynareae. Takhtajan system, Takhtajan, according to J ...
and
Mutisioideae The Mutisioideae are a subfamily in the plant family Asteraceae The family (biology), family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the Order (biology), order ...
contain 99% of the species diversity of the whole family (approximately 70%, 14%, 11% and 3% respectively). Because of the morphological complexity exhibited by this family, agreeing on generic circumscriptions has often been difficult for
taxonomist In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxon, taxa (singular ...
s. As a result, several of these genera have required multiple revisions.


Evolutionary processes

The oldest known fossils of members of Asteraceae are pollen grains from the
Late Cretaceous The Late Cretaceous (100.5–66 Year#SI prefix multipliers, Ma) is the younger of two epoch (geology), epochs into which the Cretaceous geological period, Period is divided in the geologic time scale. Stratum, Rock strata from this epoch form the ...
of
Antarctica Antarctica ( or ) is Earth's southernmost continent. It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Oc ...

Antarctica
, dated to ∼76–66 myr (
Campanian The Campanian is the fifth of six age (geology), ages of the Late Cretaceous epoch (geology), epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stage (stratigraphy) ...
to
Maastrichtian The Maastrichtian () is, in the ICS ICS may refer to: Computing * Image Cytometry Standard, a digital multidimensional image file format used in life sciences microscopy * Industrial control system, computer systems and networks used to contr ...
) and assigned to the extant genus ''Dasyphyllum''. Barreda, ''et al.'' (2015) estimated that the
crown group In phylogenetics In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Physiology, ph ...
of Asteraceae evolved at least 85.9 myr (Late Cretaceous,
Santonian The Santonian is an age (geology), age in the geologic timescale or a chronostratigraphy, chronostratigraphic stage (stratigraphy), stage. It is a subdivision of the Late Cretaceous epoch (geology), epoch or Upper Cretaceous series (stratigraphy), ...
) with a stem node age of 88–89 myr (Late Cretaceous,
Coniacian The Coniacian is an age or stage Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a week ...
). It is still unknown whether the precise cause of their great success was the development of the highly specialised capitulum, their ability to store energy as fructans (mainly
inulin Inulins are a group of naturally occurring polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrate A carbohydrate () is a biomolecule , showing alpha helices, represented by ribbons. This poten was ...

inulin
), which is an advantage in relatively dry zones, or some combination of these and possibly other factors. Heterocarpy, or the ability to produce different fruit morphs, has evolved and is common in Asteraceae. It allows seeds to be dispersed over varying distances and each are adapted to different environments, increasing chances of survival.


Etymology and pronunciation

The name Asteraceae () comes to international scientific vocabulary from New Latin, from ''Aster (genus), Aster'', the type genus, + ''wikt:-aceae#Suffix, -aceae'', a standardized suffix for plant family names in modern taxonomy. The genus name comes from the Classical Latin word , "star", which came from Ancient Greek (), "star". It refers to the star-like form of the inflorescence. The original name Compositae is still valid under the International Code of Nomenclature for algae, fungi, and plants. It refers to the "composite" nature of the capitula, which consist of a few or many individual flowers. The vernacular name ''daisy'', widely applied to members of this family, is derived from the Old English name of the daisy (''Bellis perennis''): , meaning "day's eye". This is because the petals open at dawn and close at dusk.


Distribution and habitat

Asteraceae species have a widespread distribution, from subpolar to tropical regions in a wide variety of habitats. Most occur in hot desert and cold or hot semi-desert climates, and they are found on every continent but Antarctica. They are especially numerous in tropical and subtropical regions (notably Central America, eastern Brazil, the Mediterranean region, Mediterranean, the Levant, southern Africa, central Asia, and southwestern China). The largest proportion of the species occur in the arid and semi-arid regions of subtropical and lower temperate latitudes. The Asteraceae may represent as much as 10% of Indigenous (ecology), indigenous flora in many regions of the world.


Ecology

Asteraceae are especially common in open and dry environments. Many members of Asteraceae are pollination, pollinated by insects, which explains their value in attracting beneficial insects, but pollination syndrome, anemophily is also present (e.g. ''Ragweed, Ambrosia'', ''Artemisia (genus), Artemisia''). There are many apomixis, apomictic species in the family. Seeds are ordinarily dispersed intact with the fruiting body, the cypsela. ''Seed dispersal#Wind, Anemochory'' (wind dispersal) is common, assisted by a hairy pappus. ''Seed dispersal#By animals, Epizoochory'' is another common method, in which the dispersal unit, a single cypsela (e.g. ''Bidens'') or entire capitulum (e.g. ''Arctium'') has hooks, spines or some structure to attach to the fur or plumage (or even clothes, as in the photo) of an animal just to fall off later far from its mother plant. Some members of Asteraceae are economically important as weeds. Notable in the United States are ''Senecio jacobaea'' (ragwort), ''Senecio vulgaris'' (groundsel), and ''Taraxacum'' (dandelion). Some are invasive species in particular regions, often having been introduced by human agency. Examples include various tumbleweeds, ''Bidens'', Ambrosia (plant), ragweeds, thistles, and Taraxacum officinale, dandelion. Dandelion was introduced into North America by European settlers who used the young leaves as a salad green.


Uses

Asteraceae is an economically important family, providing products such as cooking oils, leaf vegetables like lettuce, sunflower seeds, artichokes, sweetening agents, coffee substitutes and herbal teas. Several genera are of horticulture, horticultural importance, including pot marigold (''Calendula officinalis''), ''Echinacea'' (coneflowers), various daisies, Erigeron, fleabane, chrysanthemums, dahlias, zinnias, and heleniums. Asteraceae are important in herbal medicine, including ''Grindelia'', Achillea millefolium, yarrow, and many others. Commercially important plants in Asteraceae include the food crops ''Lactuca sativa'' (lettuce), ''Cichorium'' (chicory), ''Cynara scolymus'' (globe artichoke), ''Helianthus annuus'' (sunflower), ''Smallanthus sonchifolius'' (yacón), ''Carthamus tinctorius'' (safflower) and ''Helianthus tuberosus'' (Jerusalem artichoke). Plants are used as herbs and in herbal teas and other beverages. Chamomile, for example, comes from two different species: the annual ''Matricaria chamomilla'' (German chamomile) and the perennial ''Chamaemelum nobile'' (Roman chamomile). ''Calendula'' (known as pot marigold) is grown commercially for herbal teas and potpourri. ''Echinacea purpurea, Echinacea'' is used as a medicinal tea. The wormwood genus ''Artemisia (genus), Artemisia'' includes absinthe (''A. absinthium'') and tarragon (''A. dracunculus''). Winter tarragon (''Tagetes lucida''), is commonly grown and used as a tarragon substitute in climates where tarragon will not survive. Many members of the family are grown as ornamental plants for their flowers, and some are important ornamental crops for the cut flower industry. Some examples are ''Chrysanthemum'', ''Gerbera'', ''Calendula'', ''Dendranthema'', ''Argyranthemum'', ''Dahlia'', ''Tagetes'', ''Zinnia'', and many others. Many species of this family possess medicinal properties and are used as traditional parasite, antiparasitic medicine. Members of the family are also commonly featured in medical and phytochemical journals because the
sesquiterpene Sesquiterpenes are a class of terpene Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plant ...
lactone compounds contained within them are an important cause of allergic contact dermatitis. Allergy to these compounds is the leading cause of allergic contact dermatitis in florists in the US. Pollen from ragweed ''Ragweed, Ambrosia'' is among the main causes of so-called hay fever in the United States. Asteraceae are also used for some industrial purposes. French Marigold (''Tagetes patula'') is common in commercial poultry feeds and its oil is extracted for uses in cola and the cigarette industry. The genera ''Chrysanthemum'', ''Pulicaria'', ''Tagetes'', and ''Tanacetum'' contain species with useful insecticidal properties. ''Parthenium argentatum'' (guayule) is a source of hypoallergenic
latex Latex is a stable dispersion (emulsion An emulsion is a mixture of two or more liquids that are normally Miscibility, immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class o ...

latex
. Several members of the family are copious nectar (plant), nectar producers and are useful for evaluating pollinator populations during their bloom. ''Centaurea'' (knapweed), ''Helianthus annuus'' (domestic sunflower), and some species of ''Solidago'' (goldenrod) are major "honey plants" for beekeepers. ''Solidago'' produces relatively high protein pollen, which helps honey bees over winter.


References


External links

* *
Asteraceae
at th
''Angiosperm Phylogeny Website''

Compositae.org
– Compositae Working Group (CWG) and Global Compositae Database (GCD) {{Authority control Asteraceae, Asterales families Extant Campanian first appearances