Editing Mimosoideae (section)

== Acacieae ==
[[File:Acacia catechu - Köhler–s Medizinal-Pflanzen-003.jpg|thumb|''[[Senegalia catechu]]'']]
Acacieae ([[Barthélemy Charles Joseph du Mortier|Dumort.]], 1829<ref name=tt1>{{cite web|title=Taxon: Tribe Acacieae Dumort. (1829) (plant) |url=http://taxonomicon.taxonomy.nl/TaxonTree.aspx?id=100685 |website=The Taxonomicon |access-date=19 November 2015}}</ref>) is a wide-ranging, [[Polyphyly|polyphyletic]] tribe of legumes in the Mimosoideae<ref name=lew>{{cite web|last1=Lewis |first1=G.P. |title=Acacieae Dumort 1829 |url=http://www.kew.org/science-conservation/research-data/resources/legumes-of-the-world/tribe/acacieae |archive-url=https://web.archive.org/web/20150906052957/http://www.kew.org/science-conservation/research-data/resources/legumes-of-the-world/tribe/acacieae |url-status=dead |archive-date=6 September 2015 |website=Kew |access-date=19 November 2015 }}</ref> that is native to the [[pantropical|tropics]], subtropics, and warm-temperate regions. It includes five or six genera and some 1,450 species.
* Subdivision – 5 or 6 genera
** ''[[Acacia]]'' <small>Mill.</small> – type genus<ref name=lew/>
** ''[[Vachellia]]'' <small>Wight & Arn.</small>
** ''[[Senegalia]]'' <small>Rafinesque</small>
** ''[[Acaciella]]'' <small>Britton & Rose</small>
** ''[[Mariosousa]]'' <small>Seigler & Ebinger</small>
** ''[[Racosperma]]'' <small>Martius</small>

=== Relationships ===
In [[George Bentham|Bentham]]'s 1842 [[Circumscription (taxonomy)|circumscription]] of the subfamily Mimosoideae, Acacieae was one of its three constituent tribes, the others being [[Ingeae]] Benth. & Hook.f. and [[Mimoseae]] Bornn.<ref name=shin>{{cite journal|last1=Shinwari|first1=Zabta K. |last2=Jamil |first2=Khansa |last3=Zahra |first3=Nadia Batool |title=Molecular systematics of selected genera of subfamily Mimosoideae-Fabaceae |journal=Pak. J. Bot. |date=2014 |volume=46 |issue=2 |pages=591–598 |url=http://www.pakbs.org/pjbot/PDFs/46(2)/27.pdf |access-date=23 November 2015}}</ref> His Acacieae tribe of 1842 included many genera that were subsequently assigned to tribe Ingeae Benth. In 1875, however, Bentham narrowed his definition of Acacieae so as to include only ''[[Acacia sensu lato|Acacia]]'' Mill.<ref name=millerjt>{{cite journal |last1=Miller |first1=Joseph T. |last2=Bayer|first2=Randall J. |title=Molecular phylogenetics of Acacia (Fabaceae: Mimosoideae) based on the chloroplast MATK coding sequence and flanking TRNK intron spacer regions |journal=Am. J. Bot. |date=April 2001 |volume=88 |issue=4 |pages=697–705 |doi=10.2307/2657071|pmid=11302857 |jstor=2657071 }}</ref>

The only morphological character of Acacieae used to distinguish it from the Ingeae is the presence of free stamens (as in tribe Mimoseae).<ref name=shin/> In the Ingeae they are fused in the form of a tube, whereas in the Acacieae only a few species have the stamens fused at the base. Several characters of the foliage, seeds, seed pods, pollen, and stipules are shared by the two tribes.<ref name=shin/> The flower morphology of ''Acacia s.l.'' has characteristics in common with the genera ''[[Leucaena]]'', ''[[Piptadenia]]'', and ''[[Mimosa]]'' (tribe Mimoseae) and ''[[Enterolobium]]'' and ''[[Lysiloma]]'' (tribe Ingeae).<ref name=rico>{{cite journal |last1=Rico Arce |first1=M. de L. |last2=Bachman |first2=S. |title=A taxonomic revision of ''Acaciella'' (Leguminosae, Mimosoideae) |journal=Anales del Jardín Botánico de Madrid |date=2006-12-30 |volume=63 |issue=2 |pages=189–244 |doi=10.3989/ajbm.2006.v63.i2.7 |doi-access=free }}</ref>

The tribal position of monotypic genus ''[[Faidherbia]]'' <small>A. Chevalier</small> is equivocal.<ref name=lew/> It was included in the Acacieae by Vassal (1981) and Maslin et al. (2003), but Lewis & Rico Arce placed it in tribe Ingeae following Polhill (1994) and Luckow et al. (2003).<ref name=lew/><ref name=tt2>{{cite web|title=Taxon: Genus Faidherbia A. Chevalier, 1934 (plant) |url=http://taxonomicon.taxonomy.nl/TaxonTree.aspx?id=100685 |website=The Taxonomicon |access-date=19 November 2015}}</ref> In the latter case, tribe Acacieae may conform to genus ''[[Acacia sensu lato|Acacia s.l.]]'', pending the latter's relationship to other mimosoid genera. ''Faidherbia'' is troublesome as its stamens are shortly united at their base and its pollen is similar to some taxa in the Ingeae.<ref name=millerjt/>

=== Description ===
They are trees, shrubs or lianas, which may be armed or unarmed.<ref name=delin>{{cite web |last1=吴德邻 |first1=Wu Delin |last2=Nielsen |first2=Ivan C. |title=Flora of China, 6. Tribe ACACIEAE |url=http://flora.huh.harvard.edu/china/mss/volume10/FOC_10_Acacieae.pdf |publisher=Missouri Botanical Garden Press | date = 2009 |access-date=19 November 2015}}</ref> Where they have spines, these are modified stipules. In some, prickles arise from the stem's cortex and epidermis.<ref name=ww>{{cite web |last1=Armstrong |first1=W. P. |title=Botany 115 Vegetative Terminology, Modified Roots, Stems and Leaves |url=http://waynesword.palomar.edu/ecoph30a.htm |website=Waynes Word |access-date=19 November 2015 |archive-date=14 January 2016 |archive-url=https://web.archive.org/web/20160114014209/http://waynesword.palomar.edu/ecoph30a.htm |url-status=dead }}</ref> The leaves are bipinnate or are modified to vertically oriented phyllodes. A few have cladodes rather than leaves.<ref name=eol>{{cite web |title=Acacia, Thorntree |url=http://eol.org/pages/13650/details |website=EOL |access-date=22 November 2015}}</ref> [[Extrafloral nectary|Extrafloral nectaries]] may be present on the petiole and rachis, and the pinnule tips may carry protein-lipid [[Beltian body|Beltian bodies]].<ref name=ww/> The leaflets are usually opposite, and are carried on shortly stalks or are sessile. The heartwood is typically red and hard,<ref name=nic>{{cite book |editor-last1=Nicholson |editor-first1=Paul T. |editor-last2=Shaw |editor-first2=Ian |title=Ancient Egyptian materials and technology |date=2000 |publisher=Cambridge Univ. Press |location=Cambridge |isbn=9780521452571 |page=335 |edition=1. publ., repr.}}</ref> and the sap of various species hardens into gum.<ref name=eol/>

The inflorescences are dense pedunculate heads or spikes borne in axillary clusters, or are aggregated in terminal panicles.<ref name=delin/> The tetra- or pentamerous flowers are uniformly bisexual, or male and bisexual. Sepals are connate (i.e. fused) and valvate (i.e. not overlapping). The reduced petals are valvate, or rarely absent. The flowers have numerous exserted (i.e. protruding) stamens (>2× as many as the corolla lobes),<ref name=rico/> and their filaments are sometimes connate at their base (forming a short stemonozone).<!--Anthers glandular or not.--> Male flowers of some [[Neotropical realm|Neotropical]] species have a reduced staminal tube (cf. ''[[Acacia albicorticata|A. albicorticata]]'', ''[[Acacia hindsii|A. hindsii]]'', ''[[Acacia farnesiana|A. farnesiana]]'', and ''[[Senegalia picachensis|S. picachensis]]'').<ref name=rico/> Flowers are usually yellow or cream-coloured, but may be white, red, or purple.<ref name=eol/>

The ovary is sessile or stipitate (i.e. supported by a stipe), with many ovules or ovules arranged in two rows. The ovary is attached by a filiform style to a small, capitate stigma. The legume's endocarp is attached to the exocarp, but is otherwise very variable, and may be dehiscent or indehiscent. Seeds are usually elliptic to oblong and flattened to varying degrees. Seeds have a hard black-brown testa (i.e. seed coat) with a pleurogram, visible as a closed or almost closed O-shaped line. Some phyllodinous species have a colourful [[aril]] or [[elaiosome]] on the seed.<ref name=delin/>