36-408: See text Astereae is a tribe of plants in the family Asteraceae that includes annuals, biennials, perennials, subshrubs, shrubs, and trees. They are found primarily in temperate regions of the world. Plants within the tribe are present nearly worldwide divided into over 250 genera and more than 3,100 species, making it the second-largest tribe in the family behind Senecioneae . The taxonomy of
72-512: A " celestial body with rays". The capitulum, which often appears to be a single flower, is often referred to as a head . In some species, the entire head is able to pivot its floral stem in the course of the day to track the sun (like a "smart" solar panel), thus maximizing the reflectivity of the entire floral unit and further attracting flying pollinators. Nearest to the flower stem lie a series of small, usually green, scale-like bracts . These are known as phyllaries ; collectively, they form
108-506: A 3+2 scheme – above the fused corolla tube, three very long fused petals 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
144-499: A common ancestor. This is referred to as the North American clade. Guy L. Nesom and Harold E. Robinson have been involved in the recent work and are continuing to re-categorise the genera within the tribe worldwide. As of October 2024, tribe Astereae is divided into 36 accepted subtribes . Sources: FNA, E+M, UniProt, NHNSW, AFPD Asteraceae Asteraceae ( / ˌ æ s t ə ˈ r eɪ s i . iː , - ˌ aɪ / )
180-448: A few unusual species, the "head" will consist of one single disc flower; alternatively, a few species will produce both single-flowered female heads, along with multi-flowered male heads, in their "pollination strategy". The distinguishing characteristic of Asteraceae is their inflorescence , a type of specialised, composite flower head or pseudanthium , technically called a calathium or capitulum , that may look superficially like
216-428: 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 ". The presence or absence of these bracts, their distribution on
252-476: A single floral entity is in fact a composite of much smaller flowers. The "petals" or "sunrays" in an "asteraceous" head are in fact individual strap-shaped flowers called ray flowers or ray florets , and the "sun disk" is made up of smaller, radially symmetric , individual flowers called disc flowers or disc florets . The word aster means "star" in Greek, referring to the appearance of most family members as
288-441: A single flower. The capitulum is a contracted raceme composed of numerous individual sessile flowers , called florets , all sharing the same receptacle . A set of bracts forms an involucre surrounding the base of the capitulum. These are called "phyllaries", or "involucral bracts". They may simulate the sepals of the pseudanthium. These are mostly herbaceous but can also be brightly coloured (e.g. Helichrysum ) or have
324-420: 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 consists of two connate carpels . The style has two lobes. Stigmatic tissue may be located in the interior surface or form two lateral lines. The ovary
360-585: A stem node age of 88–89 mya (Late Cretaceous, Coniacian ). Asteraceae is an economically important family, providing food staples, garden plants, and herbal medicines. Species outside of their native ranges can become weedy or invasive . Members of the Asteraceae are mostly herbaceous plants, but some shrubs, vines, and trees (such as Lachanodes arborea ) do exist. Asteraceae species are generally easy to distinguish from other plants because of their unique inflorescence and other shared characteristics, such as
396-477: Is a large family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the order Asterales . The number of species in Asteraceae is rivaled only by the Orchidaceae , and which is the larger family is unclear as the quantity of extant species in each family is unknown. The Asteraceae were first described in the year 1740 and given the original name Compositae . The family
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#1733092828170432-414: Is a two- or three-lobed, strap-shaped, individual flower, found in the head of most members of the Asteraceae. The corolla of the ray flower may have two tiny, vestigial teeth, opposite to the three-lobed strap, or tongue, indicating its evolution by fusion from an ancestral, five-part corolla. In some species, the 3:2 arrangement is reversed, with two lobes, and zero or three tiny teeth visible opposite
468-411: Is actually a composite of several much smaller flowers, known as the capitulum or head . By visually presenting as a single flower, the capitulum functions in attracting pollinators , in the same manner that other "showy" flowering plants in numerous other, older, plant families have evolved to attract pollinators. The previous name for the family, Compositae , reflects the fact that what appears to be
504-533: 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 is adapted to different environments, increasing chances of survival. The original name Compositae is still valid under the International Code of Nomenclature for algae, fungi, and plants. It refers to
540-1370: Is based on Panero & Funk (2002) updated in 2014, and now also includes the monotypic Famatinanthoideae . The diamond (♦) denotes a very poorly supported node (<50% bootstrap support), the dot (•) a poorly supported node (<80%). Barnadesioideae : 9 genera, 93 species. South America , mainly the Andes . Famatinanthoideae : South America, 1 genus, 1 species Famatinanthus decussatus . Mutisioideae : 58 genera, 750 species. Absent from Europe, mostly in South America. Stifftioideae : 10 genera. South America. Wunderlichioideae : 8 genera, 24 species. Mostly in Venezuela and Guyana . Gochnatioideae : 4 or 5 genera, 90 species. Latin America and southern United States. Hecastocleidoideae : Only Hecastocleis shockleyi . Southwestern United States . Carduoideae : 83 genera, 2,500 species. Worldwide. Pertyoideae : 5 or 6 genera, 70 species. Asia. Gymnarrhenoideae : Two genera/species, Gymnarrhena micrantha ( Northern Africa , Middle East ) and Cavea tanguensis ( Eastern Himalayas ). Cichorioideae : 224 genera, 3,200 species. Worldwide. Corymbioideae : Only
576-503: Is commonly known as the aster , daisy , composite , or sunflower family . Most species of Asteraceae are herbaceous plants , and may be annual , biennial , or perennial , 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 . Their common primary characteristic
612-526: Is compound flower heads , technically known as capitula , consisting of sometimes hundreds of tiny individual florets enclosed by a whorl of protective involucral bracts . The oldest known fossils are pollen grains from the Late Cretaceous ( Campanian to Maastrichtian ) of Antarctica, dated to c. 76–66 million years ago (mya). It is estimated that the crown group of Asteraceae evolved at least 85.9 mya (Late Cretaceous, Santonian ) with
648-450: Is inferior and has only one ovule , with basal placentation . In members of the Asteraceae the fruit is achene -like, and is called a cypsela (plural cypselae ). Although there are two fused carpels, there is only one locule, and only one 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 ). In some species, however,
684-512: 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
720-432: The involucre , which serves to protect the immature head of florets during its development. The individual florets are arranged atop a dome-like structure called the receptacle . The individual florets in a head consist, developmentally, of five fused petals (rarely four); instead of sepals , they have threadlike, hairy, or bristly structures, known collectively as a pappus , (plural pappi ). The pappus surrounds
756-683: The "composite" nature of the capitula, which consist of a few or many individual flowers. 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. It is a jocular term, and sometimes reserved for those yellow composites of no particular interest. Notable individuals who referred to these flowers as "DYCs" include Oliver Sacks and Lady Bird Johnson . The U.S. National Park Service provides information to help visitors identify "Darn Yellow Composites". This Asteraceae -related article
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#1733092828170792-625: The disc in irregular symmetry, or with a weakly bilaterally symmetric arrangement. A radiate head has disc flowers surrounded by ray flowers. A ligulate head has all ligulate flowers and no disc flowers. When an Asteraceae flower head has only disc flowers that are either sterile, male, or bisexual (but not female and fertile), it is a discoid head . Disciform heads possess only disc flowers in their heads, but may produce two different sex types (male or female) within their disciform head. Some other species produce two different head types: staminate (all-male), or pistillate (all-female). In
828-613: The energy store is generally in the form of inulin rather than starch. They produce iso/ chlorogenic acid , sesquiterpene lactones , pentacyclic triterpene alcohols, various alkaloids , acetylenes (cyclic, aromatic, with vinyl end groups), tannins . They have terpenoid essential oils that never contain iridoids . Asteraceae produce secondary metabolites , such as flavonoids and terpenoids . Some of these molecules can inhibit protozoan parasites such as Plasmodium , Trypanosoma , Leishmania and parasitic intestinal worms, and thus have potential in medicine. Compositae,
864-422: The extant genus Dasyphyllum . Barreda, et al. (2015) estimated that the crown group of Asteraceae evolved at least 85.9 mya (Late Cretaceous, Santonian ) with a stem node age of 88–89 mya (Late Cretaceous, Coniacian ). It is not known 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 ), which
900-425: 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 four or five stamens . The filaments are fused to the corolla, while the anthers are generally connate ( syngenesious anthers), thus forming
936-549: The genus Corymbium , with 9 species. Cape provinces, South Africa. Asteroideae : 1,130 genera and 16,200 species. Worldwide. The family includes over 32,000 currently accepted species, in over 1,900 genera ( list ) 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 species each family includes. The four subfamilies Asteroideae , Cichorioideae , Carduoideae and Mutisioideae contain 99% of
972-424: The joined anthers of the stamens . Nonetheless, determining genera and species of some groups such as Hieracium is notoriously difficult (see " damned yellow composite " for example). Members of the family Asteraceae generally produce taproots , but sometimes they possess fibrous root systems. Some species have underground stems in the form of caudices or rhizomes . These can be fleshy or woody depending on
1008-424: The leaves. 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. In plants of the Asteraceae, what appears to be a single "daisy"-type flower
1044-473: The original name for Asteraceae, were first described in 1740 by Dutch botanist Adriaan van Royen . Traditionally, two subfamilies were recognised: Asteroideae (or Tubuliflorae) and Cichorioideae (or Liguliflorae). The latter has been shown to be extensively paraphyletic , and has now been divided into 12 subfamilies, but the former still stands. The study of this family is known as synantherology . The phylogenetic tree of subfamilies presented below
1080-434: The ovary and can, when mature and attached to a seed, adhere to animal fur or be carried by air currents, aiding in seed dispersal . The whitish, fluffy head of a dandelion , commonly blown on by children, consists of numerous seeds resting on the receptacle, each seed attached to its pappus. The pappi provide a parachute-like structure to help the seed travel from its point of origin to a more hospitable site. A ray flower
1116-465: The pappus falls off (for example in Helianthus ). Cypsela morphology is often used to help determine plant relationships at the genus and species level. The mature seeds usually have little endosperm or none. The pollen of composites is typically echinolophate, a morphological term meaning "with elaborate systems of ridges and spines dispersed around and between the apertures." In Asteraceae,
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1152-440: The receptacle, and their size and shape are all important diagnostic characteristics for genera and tribes. The florets have five petals fused at the base to form a corolla tube and they may be either actinomorphic or zygomorphic . 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
1188-499: 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 taxonomists . As a result, several of these genera have required multiple revisions. The oldest known fossils of members of Asteraceae are pollen grains from the Late Cretaceous of Antarctica , dated to ~76–66 mya ( Campanian to Maastrichtian ) and assigned to
1224-576: The species. The stems are herbaceous, aerial, branched, and cylindrical with glandular hairs, usually erect, but can be prostrate to ascending. The stems can contain secretory canals with resin , or latex , which is particularly common among the Cichorioideae . Leaves can be alternate , opposite , or whorled . They may be simple , but are often deeply lobed or otherwise incised, often conduplicate or revolute . The margins also can be entire or toothed . Resin or latex can also be present in
1260-446: The tongue. A ligulate flower is a five-lobed, strap-shaped, individual flower found in the heads of certain other asteraceous species. A ligule is the strap-shaped tongue of the corolla of either a ray flower or of a ligulate flower. A disk flower (or disc flower ) is a radially symmetric individual flower in the head, which is ringed by the ray flowers when both are present. In some species, ray flowers may be arranged around
1296-483: The tribe Astereae has been dramatically changed after both morphologic and molecular evidence suggested that large genera such as Aster , as well as many others, needed to be separated into several genera or shifted to better reflect the plants' relationships. A paper by R. D. Noyes and L. H. Rieseberg showed that most of the genera within the tribe in North America actually belong to a single clade , meaning they have
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