Atalaya calcicola foliage, 30 Dec 2012 by Mark Marathon

Atalaya hemiglauca flowers and foliage, Rockhampton, Queensland

Atalaya is a genus of about 18 species of trees and shrubs, of the soapberry plant family Sapindaceae.^[1][2][3][4] Fourteen known species grow naturally in Australia. Three known species grow naturally in southern Africa. One known species grows naturally in New Guinea and one species A. salicifolia which grows in Australia has a wider, further known distribution through nearby Timor and Malesian islands to the west of it.^[2] The latter, most widely distributed of the species was the type species, the first to be formally scientifically named and described.^[5]

Biogeography, habitats and conservation status [edit]

The twelve better known Australian species of trees, shrubs and subshrubs grow naturally in rainforests, brigalow scrubs, monsoon forests (rainforests with a dry season and deciduous trees), tropical Eucalypt savannas, coastal scrubs, some arid desert areas and in similar vegetation associations further south from the tropics.^[4] Certain species particularly occur in Australia's restricted areas of naturally high nutrient soil types, for example soils built from limestone or basalt parent materials. Areas of more fertile than average Australian soils, not surprisingly have preferentially had their native vegetation associations destroyed for converting the soils to European–Australian agricultural methods, disproportionately bringing about the decline of their specialised native plants. Two Australian species have herbarium specimen collections and informal scientific descriptions published, but are awaiting formal naming and scientific publication.

Collectively, the fourteen known Australian species range throughout the warmer parts of the continent, in the Northern Territory, Queensland, Western Australia, New South Wales and South Australia, with the exception of Tasmania and Victoria and the inclusion of parts of the semi-arid and arid zones.^[4] Some Australian species have very restricted ranges and natural habitats. A. collina Yarwun Whitewood trees, have a very restricted known range of only two populations to the west of Gladstone, Queensland, hence the populations have a national conservation status listing of "endangered" in the Australian government Environment Protection and Biodiversity Conservation Act 1999 (EPBC).^[6]

Ian D. Cowie and Glenn M. Wightman formally scientifically named and described the endemic, unique Atalaya subshrub species A. brevialata in their recently published late 2012 scientific paper.^[2] Botanists have found it growing naturally only in a very restricted area of the Darwin region of Australia. In their formal scientific description Cowie and Wightman have published the species global conservation status (IUCN) of "endangered" under the following criteria "IUCN B1, 2ab (i, ii, iii, iv, v)".^[2] A. brevialata plants have the unusual and unique nature amongst species of Atalaya of a suffruticose growing habit; meaning, in this case, a species that has evolved from an ancestral group of woody trunked, shrubs or trees into having woody growth underground only and above ground only leafy growth. They grow naturally only to subshrubs of 45 cm (18 in) height with a woody rootstock and leafy above ground growth that dies back for the dry season to the underground trunk.^[2]

In South Africa three species grow naturally. The scarcity of A. natalensis trees and their restricted range has received the global (IUCN) conservation status of "vulnerable D2".^[7] A. capensis has a global (IUCN) conservation status listing also, currently of "least concern".^[8]

In Papua New Guinea A. papuana grows naturally in coast monsoon dune scrub (coastal rainforests with deciduous trees on dune soils that become seasonally dry), tropical savanna forests and in regenerating areas of, regularly burning swamp forests and rainforests.

Naming history and classification [edit]

The Atalaya genus was first formally scientifically described by Carl L. Blume in 1847 with the Timor type specimen for the species Atalaya salicifolia.^[1] Two species were formally described in 1965 by Pieter Willem Leenhouts in preparations for the Sapindaceae treatment in Flora Malesiana.^[9] In 1981, 1985, 1991, Sally T. Reynolds scientifically described several new Australian species in two scientific journal articles and her writing of the Atalaya section of the Flora of Australia (series).^{[10][4][11][12]}

Species [edit]

Australian species information sourced from the authoritative Australian Plant Name Index and Australian Plant Census, for taxa further afield outside Australia, as for example, species in Africa and New Guinea this list may be incomplete.^[3]

• Atalaya alata (Sim) H.M.L.Forbes – South Africa^[13]
• Atalaya angustifolia S.T.Reynolds^[10] – Queensland, Australia^[14][15]
• Atalaya australiana Leenh.^[9] – Queensland, Australia^[10][16][17]
• Atalaya brevialata Cowie & Wightman^[2] – Northern Territory endemic, Australia
• Atalaya calcicola S.T.Reynolds^[10][12] – Queensland, Australia^[11][18]
• Atalaya capensis R.A.Dyer – South Africa^[8][13]
• Atalaya collina S.T.Reynolds^[12] – Queensland, Australia^[6][19]
• Atalaya hemiglauca (F.Muell.) F.Muell. ex Benth. – WA, SA, Qld, NSW, NT, Australia^[10][20][21]
• Atalaya multiflora Benth. – Qld, NSW, Australia^[10][22][21]
• Atalaya natalensis R.A.Dyer – South Africa^[7][13]
• Atalaya oligoclada S.T.Reynolds^[12] – Queensland, Australia^[23]
• Atalaya papuana (Radlk.) Leenh.^[9] – SE New Guinea^[24]
• Atalaya rigida S.T.Reynolds^[10] – Queensland, Australia^[25]
• Atalaya salicifolia (A.DC.) Blume^[1] – WA, NT, Qld, NSW, Australia;^{[10][26][21][27]} Timor, Sumbawa, Sumba, Leti, Malesia^[28]
• Atalaya sericopetala S.T.Reynolds^[10] – Queensland, Australia^[29][30]
• Atalaya variifolia (F.Muell.) F.Muell. ex Benth. – WA, NT, Qld, Australia^[10][31][32]

Species accepted by the authoritative Australian Plant Census, informally named, described and published awaiting formal publication

• Atalaya sp. Chillagoe (L.J.Webb+ 13226) Qld Herbarium (2006) – Queensland, Australia^[3]
• Atalaya sp. Scawfell Island (G.N.Batianoff+ 6098) Qld Herbarium (2006) – Queensland, Australia^[3]

References [edit]

Cited works [edit]