Acacia

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For other uses, see Acacia (disambiguation).
Racosperma
Acacia plicata.jpg
R. plicatum
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Mimosoideae
Tribe: Acacieae
Genus: Racosperma
Martius (1829)
Type species
R. verticillatum L'Her. (C.Mart.), 1789
Species

some 980 species

Acacia Distribution Map.svg
Range of the genus Racosperma
Synonyms

Acacia subg. Phyllodineae DC.[1]

R. facsiculifera shoot, showing phyllodes on the pinnate leaves, formed by dilation of the petiole and proximal part of the rachis[2]

Racosperma (from ancient Greek rhakos, "ragged" or rhakodes, "wrinkled" and sperma, "seed"),[3] commonly known as the wattles or acacias, is a monophyletic genus of 981[4] species of Acacia s.l., in the subfamily Mimosoideae of the pea family Fabaceae. All but 10 of its species are native to Australia,[4] where it constitutes the largest plant genus.[5] A number of species have been introduced to various parts of the world, and two million hectares of commercial plantations have been established.[6] The heterogeneous group[5] varies considerably in habit, from mat-like subshrubs to canopy trees in forest.[7] 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.[1]

Nomenclature[edit]

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.[8][9] 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.[10][11] Other Acacia taxa continue to be called Acacia as well.[10]

Etymology[edit]

The origin of "wattle" may be an Old Teutonic word meaning "to weave".[12] 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.[12]

Relationships[edit]

Australian species of the genus Paraserianthes s.l. are deemed its closest relatives, particularly with P. lophantha.[13] 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[edit]

They are present in all terrestrial habitats, including alpine settings, rainforests, woodlands, grasslands, coastal dunes and deserts.[7] 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.[7]

Description[edit]

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.[2] A few species have cladodes rather than leaves.[17]

Uses[edit]

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.[7] 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.[8] R. melanoxylon (Blackwood) and R. aneura (Mulga) supply some of the most attractive timbers in the genus.[7] Black wattle bark supported the tanning industries of several countries, and may supply tannins for production of waterproof adhesives.[7]

Species[edit]

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.[8] 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]

References[edit]

  • Pedley, L. (2002) A conspectus of Acacia subgen. Acacia in Australia Austrobaileya 6(2): 177-186.
  • Pedley, L. (2003) A synopsis of Racosperma C.Mart Austrobaileya 6(3): 445-496.
  1. ^ a b Pedley, Les (2003). "A synopsis of Racosperma. C.Mart. (Leguminosae: Mimosoideae).". Austrobaileya. 6 (3): 445–496. Retrieved 19 November 2015. 
  2. ^ a b 吴德邻, Wu Delin; Nielsen, Ivan C. (2009). "Flora of China, 6. Tribe ACACIEAE" (PDF). Missouri Botanical Garden Press. Retrieved 19 November 2015. 
  3. ^ Quattrocchi, Umberto (2000). R - Z. Boca Raton, FL: CRC Press. pp. 2261–2262. ISBN 9780849326783. 
  4. ^ a b Pedley, Les (February 2004). "Another view of Racosperma." (PDF). Acacia study group newsletter (90): 3. ISSN 1035-4638. Retrieved 22 November 2015. 
  5. ^ a b Murphy, Daniel J. (2008). "A review of the classification of Acacia (Leguminosae, Mimosoideae)" (PDF). Muelleria. 26 (1): 10–26. Retrieved 22 November 2015. 
  6. ^ Midgley and Turnbull
  7. ^ a b c d e f Orchard, Anthony E.; Wilson, Annette J.G. (2001). Flora of Australia. Volume 11A, Mimosaceae, Acacia part 1. Melbourne: CSIRO. pp. x–. ISBN 9780643067172. 
  8. ^ a b c Thiele, Kevin R. (February 2011). "The controversy over the retypification of Acacia Mill. with an Australian type: A pragmatic view" (PDF). Taxon. 60 (1): 194–198. Retrieved 15 November 2015. 
  9. ^ Brummitt, R. K. (December 2010). "(292) Acacia: a solution that should be acceptable to everybody" (PDF). Taxon. 59 (6): 1925–1926. Retrieved 19 November 2015. 
  10. ^ a b "The Acacia debate" (PDF). IBC2011 Congress News. Retrieved May 5, 2016. 
  11. ^ "Conserving Acacia Mill. with a conserved type: What happened in Melbourne?". Taxon. Retrieved May 5, 2016. 
  12. ^ a b Austin, Daniel F. (2004). Florida ethnobotany Fairchild Tropical Garden, Coral Gables, Florida, Arizona-Sonora Desert Museum, Tucson, Arizona: with more than 500 species illustrated by Penelope N. Honychurch ... [et al.] Boca Raton, FL: CRC Press. p. 58. ISBN 9780203491881. 
  13. ^ Brown, Gillian K., Daniel J. Murphy and Pauline Y. Ladiges (2011). "Relationships of the Australo-Malesian genus Paraserianthes (Mimosoideae: Leguminosae) identifies the sister group of Acacia sensu stricto and two biogeographical tracks.". Cladistics. 27: 380–390. doi:10.1111/j.1096-0031.2011.00349.x. 
  14. ^ Brown, Gillian K.; Murphy, Daniel J.; Miller, Joseph T.; Ladiges, Pauline Y. (1 October 2008). "Acacia s.s. and its Relationship Among Tropical Legumes, Tribe Ingeae (Leguminosae: Mimosoideae)". Systematic Botany. 33 (4): 739–751. doi:10.1600/036364408786500136. Retrieved 23 November 2015. 
  15. ^ Armstrong, W. P. "Unforgettable Acacias, A Large Genus Of Trees & Shrubs". Wayne's Word. Retrieved 17 November 2015. 
  16. ^ a b Tan, Ria. "Acacia auriculiformis, Black Wattle". Naturia. Retrieved 17 November 2015. 
  17. ^ "Acacia, Thorntree". EOL. Retrieved 22 November 2015. 
  18. ^ "Racosperma (species list)". The Plant List. Retrieved 15 November 2015.