Racosperma (from ancient Greek rhakos, "ragged" or rhakodes, "wrinkled" and sperma, "seed"), commonly known as the wattles or acacias, is a monophyletic genus of 981[7] species of Acacia s.l., in the subfamily Mimosoideae of the pea family Fabaceae. All but 10 of its species are native to Australia,[7] where it constitutes the largest plant genus.[8] A number of species have been introduced to various parts of the world, and two million hectares of commercial plantations have been established. The heterogeneous group[8] varies considerably in habit, from mat-like subshrubs to canopy trees in forest. The genus was first described from Africa by C. F. P. von Martius in 1829. Several hundred combinations in Racosperma were published by Pedley in 2003.[4]


Following a controversial decision to vote on a new type for Acacia in 2005, its species are still referred to as Acacia by some authors.[9][10] At the 2011 International Botanical Congress held in Melbourne, the minority decision to use the name Acacia rather than Racosperma for this genus, was upheld.[11][12] Other Acacia taxa continue to be called Acacia as well.[11]


The origin of "wattle" may be an Old Teutonic word meaning "to weave". From around 700 A.D. watul was used in Old English to refer to the interwoven branches and sticks which formed fences, walls and roofs. Since about 1810 it refers to the Australian legumes that provide these branches.


Australian species of the genus Paraserianthes s.l. are deemed its closest relatives, particularly with P. lophantha. The nearest relatives of Racosperma and Paraserianthes s.l. in turn include the Australian and South East Asian genera Archidendron, Archidendropsis, Pararchidendron and Wallaceodendron, all of the tribe Ingeae.[14]

Habitat and range

They are present in all terrestrial habitats, including alpine settings, rainforests, woodlands, grasslands, coastal dunes and deserts. In drier woodlands or forest they are an important component of the understory. Elsewhere they may be dominant, as in the Brigalow Belt, Myall woodlands and the eremaean Mulga woodlands.


Several of its species bear vertically oriented phyllodes, which are green, broadened leaf petioles that function like leaf blades,[15] an adaptation to hot climates and droughts.[16] Some phyllodinous species have a colourful aril on the seed.[5] A few species have cladodes rather than leaves.[17]


Aborigines of Australia have traditionally harvested the seeds of some species, to be ground into flour and eaten as a paste or baked into a cake. The seeds contain as much as 25% more protein than common cereals, and they store well for long periods due to the hard seed coats.[16] In addition to utilizing the edible seed and gum, they employed the timber for implements, weapons, fuel and musical instruments. A number of species, most notably R. mangium (Hickory wattle), R. mearnsii (Black wattle) and R. saligna (Coojong), are economically important and are widely planted globally for wood products, tannin, firewood and fodder.[9] R. melanoxylon (Blackwood) and R. aneura (Mulga) supply some of the most attractive timbers in the genus. Black wattle bark supported the tanning industries of several countries, and may supply tannins for production of waterproof adhesives.


See also: List of Acacia species

One species is native to Madagascar, 12 to Asia, and the remaining species (over 900) are native to Australasia and the Pacific Islands.[9] Along with the re-classifications of the Acacia genus, many of the species names are reclassified as well. Acacia pulchella, for example, becomes Racosperma pulchellum. The species of Racosperma include:[18]