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{{Taxobox
| color = lightgreen
| name = Sunflowers
| image = Aster-alpinus.JPG
| image_width = 250px
| image_caption = ''[[Aster alpinus]]''
| regnum = [[Plant]]ae
| divisio = [[Flowering plant|Magnoliophyta]]
| classis = [[Magnoliopsida]]
| ordo = [[Asterales]]
| familia = '''Asteraceae'''
| familia_authority = [[Martynov]], 1820
| synonyms = ''Compositae'' <small>[[Giseke]]</small>
| type_genus = ''[[Aster (flower)|Aster]]''
| type_genus_authority= [[Carolus Linnaeus|L.]]
| diversity = About 1500 genera and 23,000 species
| diversity_link = List of Asteraceae genera
| subdivision_ranks = Subfamilies
| subdivision =
[[Barnadesioideae]]<br>
[[Cichorioideae]]<br>
:Tribe [[Arctotidae]]<br>
:Tribe [[Cardueae]]<br>
:Tribe [[Eremothamneae]]<br>
:Tribe [[Lactuceae]]<br>
:Tribe [[Liabeae]]<br>
:Tribe [[Mutisieae]]<br>
:Tribe [[Tarchonantheae]]<br>
:Tribe [[Vernonieae]]<br>
[[Asteroideae]]<br>
:Tribe [[Anthemideae]]<br>
:Tribe [[Astereae]]<br>
:Tribe [[Calenduleae]]<br>
:Tribe [[Eupatorieae]]<br>
:Tribe [[Gnaphalieae]]<br>
:Tribe [[Helenieae]]<br>
:Tribe [[Heliantheae]]<br>
:Tribe [[Inuleae]]<br>
:Tribe [[Plucheae]]<br>
:Tribe [[Senecioneae]]<br>
:Tribe [[Tageteae]]<br>
'''See also [[List of Asteraceae genera]]'''
}}
The family '''Asteraceae''' or, alternatively, '''Compositae''', known as the '''aster''', '''daisy''' or '''sunflower family''', is a taxon of [[dicot]]yledonous [[flowering plant]]s. The family name is derived from the genus ''[[Aster (flower)|Aster]]'' and refers to the [[star]]-shaped flower head of its members, epitomized well by the [[Bellis perennis|daisy]]. The Asteraceae is the second largest family in the Division [[Flowering plant|Magnoliophyta]], with some 1,100 genera (see the [[List_of_Asteraceae_genera]]) and over 20,000 recognized species. Only the orchid family ([[Orchidaceae]]) is larger, with about 25,000 described species <ref>[http://www.flmnh.ufl.edu/orchidatol/ Introduction to assembling the Tree of Life: Orchidaceae]</ref>.
== Description ==
Plants belonging to the Asteraceae share ''all'' the following characteristics (Judd et al., 1999). None of these traits, taken separately, can be considered [[Synapomorphy|synapomorphic]].
* The [[inflorescence]] is an involucrate [[capitulum]] ([[head (botany)|flower head]])
* Tubular/disc florets are actinomorphic, ligulate/ray florets are zygomorphic
* [[Anther]]s are syngenesious, i.e. with the [[stamens]] fused together at their edges, forming a tube
* The [[ovary (plants)|ovary]] has basal arrangement of the [[ovule]]s
* One [[ovule]] per ovary
* The calyx ([[sepal]]s) of the florets are modified to form a [[pappus]], a tuft of hairs, which often appears on the mature [[fruit]]
* The [[fruit]] is an [[achene]]
* In the essential oils [[Sesquiterpene]]s are present, but iridoids are lacking.
[[Image:Bidens_flwr.jpg|thumb|left|A typical Asteraceae flower head (here ''[[Bidens torta]]'') showing the individual flowers]]
[[Image:Flower head.jpg|thumb|left|Flowers of a [[sunflower]] with different forms and phases (sterile ray flowers, disc flowers in female, male and unopened phases)]]
The most common characteristic of all these plants is an inflorescence or '''flower head'''; a densely packed cluster of many small, individual [[flowers]], usually called '''florets''' (meaning "small flowers").
Plants in the family Asteraceae typically have one or both of two kinds of ''florets''. The outer perimeter of a flower head like that of a [[sunflower]] is composed of florets possessing a long strap-like [[petal]], termed a '''ligule'''; these are the '''ray florets'''. The inner portion of the flower head (or ''disc'') is composed of small flowers with tubular [[petal|corollas]]; these are the '''disc florets'''. The composition of asteraceous inflorescences varies from all ray flowers (like [[dandelion]]s, genus ''Taraxacum'') to all disc flowers (like [[pineapple weed]]s).
The composite nature of the inflorescences of these plants led early taxonomists to call this family the Compositae. Although the rules governing naming conventions for plant families state that the name should come from the [[type (botany)|type genus]], in this case ''Aster'' and thus Asteraceae. However, the long prevailing name Compositae is also authorized as an alternative family name ([[ICBN]] Art. 18.6).
The numerous genera are divided into about 13 tribes. Only one of these, Lactuceae, is considered distinct enough to be a subfamily (subfamily Cichorioideae); the remainder, which are mostly overlapping, are put in the subfamily Asteroideae (Wagner, Herbst, and Sohmer, 1990).
==Uses==
Commercially important plants in the Asteraceae include the food crops [[lettuce]], [[chicory]], [[globe artichoke]], [[sunflower]], [[yacón]], [[safflower]] and [[Jerusalem artichoke]]. [[Guayule]] is a source of [[hypoallergenic]] [[latex]].
Many members of Asteraceae 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 [[beekeeper]]s. ''Solidago'' produces relatively high protein [[pollen]], which helps [[honey bee]]s overwinter.
Many members of the family are grown as ornamental plants for their flowers, e.g., [[chrysanthemum]]s and some are important ornamental crops for the cut flower industry. Some Asteraceae are economically important in the sense that they are considered noxious weeds, e.g., [[dandelion]]s.
<br clear= all />
[[Image:Ray.floret01.jpg|thumb|left|Ray floret : <small>A = ovary; B = pappus; C = theca; D = ligule; E = style with stigma </small>]]
[[Image:Disc floret01.jpg||thumb|right|Disc floret : <small> A = ovary; B = tube of corolla with teeth of the corolla; C = theca; D = style with stigma </small>]]
<br clear= all />
== Footnote ==
[[Image:Gnaphalium supinum0.jpg|thumb|right|200px|''Helichrysum petiolare'']]
<div class="references-small" style="column-count:2;-moz-column-count:2;">
<references/>
</div>
== References ==
* [http://www.itis.usda.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=35420 ITIS report 2002-09-10]
* International Code of Botanical Nomenclature (ICBN, St. Louis Code). 1999. [http://www.bgbm.fu-berlin.de/iapt/nomenclature/code/SaintLouis/0000St.Luistitle.htm website] (Published as ''Regnum Vegetabile 138''. Koeltz Scientific Books, Königstein. ISBN 3-904144-22-7)
* Walters, Dirk R. and David J. Keil (1996). ''Vascular plant taxonomy''. 4th ed. Kendall/Hunt Publishing Company. Dubuque, Iowa.
* Wagner,W.L., D.R. Herbst, and S.H. Sohmer. 1990. ''Manual of the Flowering Plants of Hawai‘i'', Vol. I. University of Hawaii Press, Honolulu. 988 pp.
* Judd, W.S., C.S. Campbell, E.A. Kellogg, and P.F. Stevens. 1999. Plant Systematics: A Phylogenetic Approach. Sinauer Associates, Sunderland, MA.
* D. J. N. Hind, C. Jeffrey & G. V. Pope (eds.), Advances in Compositae systematics. - Royal Bot. Gardens, Kew, 469 pp., 1995
==External links==
* {{dmoz|/Science/Biology/Flora_and_Fauna/Plantae/Magnoliophyta/Magnoliopsida/Asteraceae/}}
{{commonscat|Asteraceae}}
<!---->
[[Category:Plant families]]
[[Category:Asteraceae| ]]
| color = lightgreen
| name = Sunflowers
| image = Aster-alpinus.JPG
| image_width = 250px
| image_caption = ''[[Aster alpinus]]''
| regnum = [[Plant]]ae
| divisio = [[Flowering plant|Magnoliophyta]]
| classis = [[Magnoliopsida]]
| ordo = [[Asterales]]
| familia = '''Asteraceae'''
| familia_authority = [[Martynov]], 1820
| synonyms = ''Compositae'' <small>[[Giseke]]</small>
| type_genus = ''[[Aster (flower)|Aster]]''
| type_genus_authority= [[Carolus Linnaeus|L.]]
| diversity = About 1500 genera and 23,000 species
| diversity_link = List of Asteraceae genera
| subdivision_ranks = Subfamilies
| subdivision =
[[Barnadesioideae]]<br>
[[Cichorioideae]]<br>
:Tribe [[Arctotidae]]<br>
:Tribe [[Cardueae]]<br>
:Tribe [[Eremothamneae]]<br>
:Tribe [[Lactuceae]]<br>
:Tribe [[Liabeae]]<br>
:Tribe [[Mutisieae]]<br>
:Tribe [[Tarchonantheae]]<br>
:Tribe [[Vernonieae]]<br>
[[Asteroideae]]<br>
:Tribe [[Anthemideae]]<br>
:Tribe [[Astereae]]<br>
:Tribe [[Calenduleae]]<br>
:Tribe [[Eupatorieae]]<br>
:Tribe [[Gnaphalieae]]<br>
:Tribe [[Helenieae]]<br>
:Tribe [[Heliantheae]]<br>
:Tribe [[Inuleae]]<br>
:Tribe [[Plucheae]]<br>
:Tribe [[Senecioneae]]<br>
:Tribe [[Tageteae]]<br>
'''See also [[List of Asteraceae genera]]'''
}}
The family '''Asteraceae''' or, alternatively, '''Compositae''', known as the '''aster''', '''daisy''' or '''sunflower family''', is a taxon of [[dicot]]yledonous [[flowering plant]]s. The family name is derived from the genus ''[[Aster (flower)|Aster]]'' and refers to the [[star]]-shaped flower head of its members, epitomized well by the [[Bellis perennis|daisy]]. The Asteraceae is the second largest family in the Division [[Flowering plant|Magnoliophyta]], with some 1,100 genera (see the [[List_of_Asteraceae_genera]]) and over 20,000 recognized species. Only the orchid family ([[Orchidaceae]]) is larger, with about 25,000 described species <ref>[http://www.flmnh.ufl.edu/orchidatol/ Introduction to assembling the Tree of Life: Orchidaceae]</ref>.
== Description ==
Plants belonging to the Asteraceae share ''all'' the following characteristics (Judd et al., 1999). None of these traits, taken separately, can be considered [[Synapomorphy|synapomorphic]].
* The [[inflorescence]] is an involucrate [[capitulum]] ([[head (botany)|flower head]])
* Tubular/disc florets are actinomorphic, ligulate/ray florets are zygomorphic
* [[Anther]]s are syngenesious, i.e. with the [[stamens]] fused together at their edges, forming a tube
* The [[ovary (plants)|ovary]] has basal arrangement of the [[ovule]]s
* One [[ovule]] per ovary
* The calyx ([[sepal]]s) of the florets are modified to form a [[pappus]], a tuft of hairs, which often appears on the mature [[fruit]]
* The [[fruit]] is an [[achene]]
* In the essential oils [[Sesquiterpene]]s are present, but iridoids are lacking.
[[Image:Bidens_flwr.jpg|thumb|left|A typical Asteraceae flower head (here ''[[Bidens torta]]'') showing the individual flowers]]
[[Image:Flower head.jpg|thumb|left|Flowers of a [[sunflower]] with different forms and phases (sterile ray flowers, disc flowers in female, male and unopened phases)]]
The most common characteristic of all these plants is an inflorescence or '''flower head'''; a densely packed cluster of many small, individual [[flowers]], usually called '''florets''' (meaning "small flowers").
Plants in the family Asteraceae typically have one or both of two kinds of ''florets''. The outer perimeter of a flower head like that of a [[sunflower]] is composed of florets possessing a long strap-like [[petal]], termed a '''ligule'''; these are the '''ray florets'''. The inner portion of the flower head (or ''disc'') is composed of small flowers with tubular [[petal|corollas]]; these are the '''disc florets'''. The composition of asteraceous inflorescences varies from all ray flowers (like [[dandelion]]s, genus ''Taraxacum'') to all disc flowers (like [[pineapple weed]]s).
The composite nature of the inflorescences of these plants led early taxonomists to call this family the Compositae. Although the rules governing naming conventions for plant families state that the name should come from the [[type (botany)|type genus]], in this case ''Aster'' and thus Asteraceae. However, the long prevailing name Compositae is also authorized as an alternative family name ([[ICBN]] Art. 18.6).
The numerous genera are divided into about 13 tribes. Only one of these, Lactuceae, is considered distinct enough to be a subfamily (subfamily Cichorioideae); the remainder, which are mostly overlapping, are put in the subfamily Asteroideae (Wagner, Herbst, and Sohmer, 1990).
==Uses==
Commercially important plants in the Asteraceae include the food crops [[lettuce]], [[chicory]], [[globe artichoke]], [[sunflower]], [[yacón]], [[safflower]] and [[Jerusalem artichoke]]. [[Guayule]] is a source of [[hypoallergenic]] [[latex]].
Many members of Asteraceae 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 [[beekeeper]]s. ''Solidago'' produces relatively high protein [[pollen]], which helps [[honey bee]]s overwinter.
Many members of the family are grown as ornamental plants for their flowers, e.g., [[chrysanthemum]]s and some are important ornamental crops for the cut flower industry. Some Asteraceae are economically important in the sense that they are considered noxious weeds, e.g., [[dandelion]]s.
<br clear= all />
[[Image:Ray.floret01.jpg|thumb|left|Ray floret : <small>A = ovary; B = pappus; C = theca; D = ligule; E = style with stigma </small>]]
[[Image:Disc floret01.jpg||thumb|right|Disc floret : <small> A = ovary; B = tube of corolla with teeth of the corolla; C = theca; D = style with stigma </small>]]
<br clear= all />
== Footnote ==
[[Image:Gnaphalium supinum0.jpg|thumb|right|200px|''Helichrysum petiolare'']]
<div class="references-small" style="column-count:2;-moz-column-count:2;">
<references/>
</div>
== References ==
* [http://www.itis.usda.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=35420 ITIS report 2002-09-10]
* International Code of Botanical Nomenclature (ICBN, St. Louis Code). 1999. [http://www.bgbm.fu-berlin.de/iapt/nomenclature/code/SaintLouis/0000St.Luistitle.htm website] (Published as ''Regnum Vegetabile 138''. Koeltz Scientific Books, Königstein. ISBN 3-904144-22-7)
* Walters, Dirk R. and David J. Keil (1996). ''Vascular plant taxonomy''. 4th ed. Kendall/Hunt Publishing Company. Dubuque, Iowa.
* Wagner,W.L., D.R. Herbst, and S.H. Sohmer. 1990. ''Manual of the Flowering Plants of Hawai‘i'', Vol. I. University of Hawaii Press, Honolulu. 988 pp.
* Judd, W.S., C.S. Campbell, E.A. Kellogg, and P.F. Stevens. 1999. Plant Systematics: A Phylogenetic Approach. Sinauer Associates, Sunderland, MA.
* D. J. N. Hind, C. Jeffrey & G. V. Pope (eds.), Advances in Compositae systematics. - Royal Bot. Gardens, Kew, 469 pp., 1995
==External links==
* {{dmoz|/Science/Biology/Flora_and_Fauna/Plantae/Magnoliophyta/Magnoliopsida/Asteraceae/}}
{{commonscat|Asteraceae}}
<!---->
[[Category:Plant families]]
[[Category:Asteraceae| ]]
