Vachellia


Vachellia is a genus of flowering plants in the legume family, Fabaceae, commonly known as thorn trees or acacias. It belongs to the subfamily Mimosoideae. Its species were considered members of genus Acacia until 2009. Vachellia can be distinguished from other acacias by its capitate inflorescences and spinescent stipules. Before discovery of the New World, Europeans in the Mediterranean region were familiar with several species of Vachellia, which they knew as sources of medicine, and had names for them that they inherited from the Greeks and Romans.
The wide-ranging genus occurs in a variety of open, tropical to subtropical habitats, and is locally dominant. In parts of Africa, Vachellia species are shaped progressively by grazing animals of increasing size and height, such as gazelle, gerenuk, and giraffe. The genus in Africa has thus developed thorns in defence against such herbivory.

Nomenclature

By 2005, taxonomists had decided that Acacia sensu lato should be split into at least five separate genera. The ICN dictated that under these circumstances, the name of Acacia should remain with the original type, which was Acacia nilotica. However, that year the General Committee of the IBC decided that Acacia should be given a new type so that the ~920 species of Australian acacias would not need to be renamed Racosperma. This decision was opposed by 54.9% or 247 representatives at its 2005 congress, while 45.1% or 203 votes were cast in favor. However, since a 60% vote was required to override the committee, the decision was carried, and a nom. cons. propositum was listed in Appendix III. The 2011 congress voted 373 to 172 to uphold the 2005 decision, which means that the name Acacia and a new type follow the majority of the species in Acacia sensu lato, rather than this genus. However, some members of the botanical community remain unconvinced, and the use of Acacia in the scientific literature continues to exceed the use of the new generic names.

Description

The members of Vachellia are trees or shrubs, sometimes climbing, and are always armed. Younger plants, especially, are armed with spines which are modified stipules, situated near the leaf bases. Some are also armed with paired, recurved prickles. The leaves are alternate and bipinnately arranged, and their pinnae are usually opposite. The racemose inflorescences usually grow from the leaf axils. The yellow or creamy white flowers are produced in spherical heads, or seldom in elongate spikes, which is the general rule in the related genus Senegalia. The flowers are typically bisexual with numerous stamens, but unisexual flowers have been noted in V. nilotica. The calyx and corolla are usually 4 to 5-lobed. Glands are usually present on the rachis and the upper side of the petiole. The seed pod may be straight, curved or curled, and either dehiscent or indehiscent.

Species list

Of the 163 species currently assigned to Vachellia, 52 are native to the Americas, 83 to Africa, Madagascar and the Mascarene Islands, 32 to Asia and 9 to Australia and the Pacific Islands. Vachellia comprises the following species:Vachellia abyssinica Kyal. & Boatwr.—flat top acacia
  • * subsp. abyssinica Kyal. & Boatwr.
  • * subsp. calophylla Kyal. & Boatwr.Vachellia acuifera Seigler & Ebinger—Bahama acacia, cassip, pork-and-doughboy, rosewoodVachellia albicortata Seigler & EbingerVachellia allenii Seigler & Ebinger—Allen acaciaVachellia amythethophylla Kyal. & Boatwr.Vachellia ancistroclada Kyal. & Boatwr.Vachellia anegadensis Seigler & Ebinger—Anegada acacia, blackbrush-wattle, pokemeboyVachellia antunesii Kyal. & Boatwr.Vachellia arenaria Kyal. & Boatwr.—sand acaciaVachellia aroma Seigler & Ebinger
  • * var. aroma Gillies ex Hook. & Arn.
  • * var. huarango Ruíz & J.Macbr.Vachellia astringens Speg.Vachellia baessleri Clarke, Siegler & EbingerVachellia barahonensis Seigler & EbingerVachellia bavazzanoi Kyal. & Boatwr.Vachellia belairioides Seigler & Ebinger—Bellair acaciaVachellia bellula Boatwr.Vachellia biaciculata Seigler & EbingerVachellia bidwillii Kodela—corkwood wattle, dogwood. "'Waneu', of the aboriginals of Central Queensland; 'Yadthor', of those of the Cloncurry River, Northern Queensland."Vachellia bilimekii Seigler & EbingerVachellia bolei Ragupathy, Seigler, Ebinger & MaslinVachellia borleae Kyal. & Boatwr.—sticky acacia, named for the collector Jeanne M. Borle.Vachellia brandegeana Seigler & Ebinger—Baja California acaciaVachellia bravoensis Seigler & EbingerVachellia bricchettiana Kyal. & Boatwr.Vachellia bucheri Seigler & Ebinger—Bucher acaciaVachellia bullockii Kyal. & Boatwr.
  • * var. bullockii Kyal. & Boatwr.
  • * var. induta Kyal. & Boatwr.Vachellia burttii Kyal. & Boatwr.Vachellia bussei Kyal. & Boatwr.Vachellia californica Seigler & EbingerVachellia campechiana Seigler & Ebinger—boatthorn acacia, spoon-thorn acacia
  • * f. campechiana Seigler & Ebinger
  • * f. houghii Seigler & EbingerVachellia caurina Seigler & EbingerVachellia caven Seigler & Ebinger
  • * var. caven Seigler & Ebinger
  • * var. dehiscens Seigler & Ebinger
  • * var. microcarpa Seigler & Ebinger
  • * var. stenocarpa Seigler & EbingerVachellia cernua Kyal. & Boatwr.Vachellia chiapensis Seigler & Ebinger—Chiapas acaciaVachellia choriophylla Seigler & Ebinger—cinnecord acacia, Florida acacia, cinnecordVachellia clarksoniana KodelaVachellia collinsii Seigler & Ebinger—Collins acaciaVachellia constricta Seigler & Ebinger—Whitethorn acacia, Mescat acaciaVachellia cookii Seigler & Ebinger—Cook acacia, cockspur acaciaVachellia cornigera Seigler & Ebinger—bullhorn wattle, bull's-horn acacia, bull-horn thorn, oxhorn acaciaVachellia cucuyo Seigler & Ebinger—Cucuyo acaciaVachellia curvifructa Seigler & EbingerVachellia daemon Seigler & Ebinger—Camagüey acaciaVachellia davyi Kyal. & Boatwr.—corky-bark acaciaVachellia ditricha KodelaVachellia dolichocephala Kyal. & Boatwr.Vachellia douglasica KodelaVachellia drepanolobium P.J.H. Hurter—whistling thornVachellia dyeri Kyal. & Boatwr.Vachellia eburnea P. Hurter & Mabb.Vachellia ebutsiniorum Kyal. & Boatwr.—Ebutsini acaciaVachellia edgeworthii Kyal. & Boatwr.Vachellia elatior Kyal. & Boatwr.
  • * subsp. elatior Kyal. & Boatwr.
  • * subsp. turkanae Kyal. & Boatwr.Vachellia erioloba P.J.H. Hurter—camel thorn Vachellia erythrophloea Kyal. & Boatwr.Vachellia etbaica Kyal. & Boatwr.—savannah thorn
  • * subsp. australis Kyal. & Boatwr.
  • * subsp. etbaica Kyal. & Boatwr.
  • * subsp. platycarpa Kyal. & Boatwr.
  • * subsp. uncinata Kyal. & Boatwr.Vachellia exuvialis Kyal. & Boatwr.—flaky-bark acaciaVachellia farnesiana Wight & Arn.—huisache
  • * var. farnesiana Wight & Arn.
  • * var. guanacastensis Wight & Arn.
  • * var. minuta Wight & Arn.
  • * var. pinetorum Wight & Arn.—pineland wattleVachellia fischeri Kyal. & Boatwr.—flat-topped thornVachellia flava Kyal. & Boatwr.Vachellia gentlei Seigler & Ebinger—gentle acaciaVachellia gerrardii P.J.H. Hurter—red acacia
  • * var. calvescens P.J.H. Hurter
  • * var. gerrardii P.J.H. Hurter
  • * var. latisiliqua P.J.H. HurterVachellia glandulifera Seigler & EbingerVachellia globulifera Seigler & Ebinger—globular acaciaVachellia grandicornuta Seigler & Ebinger—horned-thorn acaciaVachellia guanacastensis Seigler & EbingerVachellia gummifera Kyal. & Boatwr.—gum-bearing acaciaVachellia haematoxylon Seigler & Ebinger—gray camel thorn, giraffe thornVachellia harmandiana Maslin, Seigler & EbingerVachellia hebeclada Kyal. & Boatwr.—candle-pod acacia
  • * subsp. chobiensis Kyal. & Boatwr.
  • * subsp. hebeclada Kyal. & Boatwr.
  • * subsp. tristis Kyal. & Boatwr.Vachellia hindsii Seigler & Ebinger—Hinds acaciaVachellia hockii Seigler & EbingerVachellia horrida Kyal. & Boatwr.—long white-galled acacia
  • * subsp. benadirensis Kyal. & Boatwr.
  • * subsp. horrida Kyal. & Boatwr.Vachellia hydaspica AliVachellia inopinata Maslin, Seigler & EbingerVachellia insulae-iacobi Seigler & EbingerVachellia jacquemontii ali—baonḷī, raati-banwaliVachellia janzenii Seigler & Ebinger—Janzen acaciaVachellia karroo Banfi & Galasso—Karroo BushVachellia kingii Maslin, Seigler & EbingerVachellia kirkii Kyal. & Boatwr.—flood plain acacia
  • * subsp. kirkii Kyal. & Boatwr.
  • ** var. kirkii Kyal. & Boatwr.
  • ** var. sublaevis Kyal. & Boatwr.
  • * subsp. mildbraedii Kyal. & Boatwr.Vachellia koltermanii R. García, M. Mejía, Ebinger, & SeiglerVachellia kosiensis Kyal. & Boatwr.—dune acacia, dune sweet-thornVachellia lahai Kyal. & Boatwr.—red-thorn acaciaVachellia lasiopetala Kyal. & Boatwr.Vachellia latispina Kyal. & Boatwr.Vachellia leucophloea Maslin, Seigler & Ebinger—pilang
  • * var. leucophloea Maslin, Seigler & Ebinger
  • * var. microcephala Maslin, Seigler & EbingerVachellia leucospira Kyal. & Boatwr.Vachellia luederitzii Kyal. & Boatwr.—bastard umbrella thorn
  • * var. luederitzii Kyal. & Boatwr.—Kalahari-sand acacia
  • * var. retinens Kyal. & Boatwr.—balloon-thorn acaciaVachellia macracantha Seigler & Ebinger—longspine acacia, French casha, long-spine acacia, porknut, cambrón, long-spined acacia, parknut, wild tamarind, Creole casha, Spanish casha, steel acacia, stink casha, strink cashaVachellia macrothyrsa Kyal. & Boatwr.Vachellia malacocephala Kyal. & Boatwr.—black-galled acaciaVachellia mayana Seigler & Ebinger—Maya AcaciaVachellia mbuluensis Kyal. & Boatwr.—hairy-galled acaciaVachellia melanoceras Seigler & Ebinger—blackthorn acacia, bullhorn acaciaVachellia montana Kyal. & Boatwr.Vachellia myaingii Maslin, Seigler & EbingerVachellia myrmecophila Boatwr.Vachellia natalitia Kyal. & Boatwr.—pale-bark acacia, pale-bark sweet thornVachellia nebrownii Seigler & Ebinger—water acacia, water thornVachellia negrii Kyal. & Boatwr.
  • Vachellia nilotica P.J.H. Hurter & Mabb.—scented-pod acacia, gum Arabic tree, babul, Amrad gum, thorny mimosa of India
  • * subsp. adstringens P.J.H. Hurter & Mabb.
  • * subsp. cupressiformis P.J.H. Hurter & Mabb.
  • * subsp. hemispherica P.J.H. Hurter & Mabb.
  • * subsp. indica P.J.H. Hurter & Mabb.—Babul, prickly acacia
  • * subsp. kraussiana P.J.H. Hurter & Mabb.
  • * subsp. leiocarpa P.J.H. Hurter & Mabb.
  • * subsp. nilotica P.J.H. Hurter & Mabb.
  • * subsp. subalata P.J.H. Hurter & Mabb.
  • * subsp. tomentosa P.J.H. Hurter & Mabb.Vachellia nubica Kyal. & Boatwr.Vachellia oerfota Kyal. & Boatwr.
  • * var. brevifolia Kyal. & Boatwr.
  • * var. oerfota Kyal. & Boatwr.Vachellia origena Kyal. & Boatwr.Vachellia ormocarpoides Kyal. & Boatwr.—Leolo thornVachellia oviedoensis Seigler & EbingerVachellia pacensis Seigler & EbingerVachellia pachyphloia Kodela
  • * subsp. brevipinnula Kodela
  • * subsp. pachyphloia KodelaVachellia pallidifolia KodelaVachellia paolii Kyal. & Boatwr.
  • * subsp. paolii Kyal. & Boatwr.
  • * subsp. paucijuga Kyal. & Boatwr.Vachellia pennatula Seigler & Ebinger—feather acacia
  • * var. parvicephala Seigler & Ebinger
  • * var. pennatula Seigler & EbingerVachellia permixta Kyal. & Boatwr.—slender acaciaVachellia pilispina Kyal. & Boatwr.—mpandeVachellia polypyrigenes Seigler & EbingerVachellia prasinata Kyal. & Boatwr.Vachellia pringlei Seigler & Ebinger—Pringle acacia
  • * var. californica —California Pringle acacia
  • * var. pringlei Seigler & Ebinger—typical Pringle acaciaVachellia pseudofistula Kyal. & Boatwr.—ant-galled acaciaVachellia qandalensis Kyal. & Boatwr.Vachellia quintanilhae Kyal. & Boatwr.Vachellia reficiens Kyal. & Boatwr.—red-bark acacia
  • * subsp. misera Kyal. & Boatwr.
  • * subsp. reficiens Kyal. & Boatwr.Vachellia rehmanniana Kyal. & Boatwr.—silky acaciaVachellia rigidula Seigler & Ebinger—blackbrush acacia, blackbrushVachellia robbertsei Kyal. & Boatwr.—Sekhukhune acaciaVachellia robusta Kyal. & Boatwr.—splendid acacia
  • * subsp. clavigera Kyal. & Boatwr.—river acacia
  • * subsp. robusta Kyal. & Boatwr.—robust acacia
  • * subsp. usambarensis Kyal. & Boatwr.Vachellia roigii Seigler & Ebinger—Roig acaciaVachellia rorudiana Seigler & Ebinger—Galapagos acaciaVachellia ruddiae Seigler & Ebinger—Rudd acaciaVachellia schaffneri Seigler & Ebinger—Schaffner's wattle, twisted acacia
  • * var. bravoensis Seigler & Ebinger
  • * var. schaffneri Seigler & EbingerVachellia schottii Seigler & Ebinger—Schott's wattleVachellia sekhukhuniensis Kyal. & Boatwr.—Sekhukhune thornVachellia seyal P.J.H. Hurter—white whistling thorn
  • * var. fistula P.J.H. Hurter
  • * var. seyal P.J.H. HurterVachellia siamensis Maslin, Seigler & EbingerVachellia sieberiana Kyal. & Boatwr.—longpod thorn, false paperbark thorn
  • * var. sieberiana Kyal. & Boatwr.
  • * var. villosa Kyal. & Boatwr.
  • * var. woodii Kyal. & Boatwr.—paperbark acacia, paperbark thornVachellia sphaerocephala Seigler & Ebinger—roundhead acacia, bee wattleVachellia stuhlmannii Kyal. & Boatwr.—olive-barked thorn, vlei acaciaVachellia suberosa Kodela—corkybark wattleVachellia sutherlandii Kodela—corkwood wattleVachellia swazica Kyal. & Boatwr.—Swazi acaciaVachellia tenuispina Kyal. & Boatwr.—turf acaciaVachellia tephrophylla Kyal. & Boatwr.Vachellia theronii Boatwr.—slender mountain thornVachellia tomentosa Maslin, Seigler & Ebinger—klampisVachellia torrei Kyal. & Boatwr.—Mozambique sticky thornVachellia tortilis Galasso & Banfi—umbrella thorn, umbrella acacia
  • * subsp. heteracantha Galasso & Banfi
  • * subsp. raddiana Galasso & Banfi
  • ** var. pubescens Galasso & Banfi
  • ** var. raddiana Galasso & Banfi
  • * subsp. spirocarpa Galasso & Banfi
  • ** var. crinita Galasso & Banfi
  • ** var. spirocarpa Galasso & Banfi
  • * subsp. tortilis Galasso & BanfiVachellia tortuosa Seigler & Ebinger—twisted acacia, acacia bush, casia, catclaw, Dutch casha, huisachillo, Rio Grande acacia, sweet briar, sweet-briar, wild poponaxVachellia turnbulliana Kyal. & Boatwr.—velvet pod acaciaVachellia valida KodelaVachellia vernicosa Seigler & Ebinger—viscid acaciaVachellia viguieri Boatwr.Vachellia villaregalis Seigler & EbingerVachellia walwalensis Kyal. & Boatwr.Vachellia xanthophloea P.J.H. Hurter—fever treeVachellia zanzibarica Kyal. & Boatwr.—coastal whistling thorn
  • * var. microphylla Kyal. & Boatwr.
  • * var. zanzibarica Kyal. & Boatwr.Vachellia zapatensis Seigler & Ebinger

''Incertae sedis''

These species are suspected to belong to Vachellia, but have not been formally transferred.Acacia callicoma Meisn.Acacia harala Thulin & GifriAcacia hunteri Oliv.Acacia johnwoodii BoulosAcacia planifrons Koenig ex Wight & Arn.Acacia pseudo-eburnea J.R. Drumm. ex DunnAcacia tanjorensis Ragup., Thoth. & Mahad.Acacia yemenensis Boulos

Hybrids

Vachellia × cedilloi Seigler & EbingerVachellia campechiana × pennatulaVachellia erioloba × haematoxylonVachellia × gladiata Seigler & EbingerVachellia kirkii × seyalVachellia macracantha × pennatulaVachellia seyal var. fistula × xanthophloeaVachellia × standleyi Seigler & Ebinger