minutum. This taxon was moved to Acacia minuta by R. Mitchel Beauchamp in 1980. Beauchamp also subsumed A. smallii under A. minuta subsp. densiflora, although this was not widely followed. Acacia smallii was used in the U.S. for the 'native' A. farnesiana growing in the drylands west of Louisiana, but at the same time, the taxon A. farnesiana was recognised in the U.S. for purportedly imported non-native plants originally cultivated in the Southeastern U.S. as ornamentals and later thought naturalised there. Additionally, in Florida, A. pinetorum was recognised as a rare endemic native. A paper in 1989 by H. D. Clarke, D. S. Seigler and J. E. Ebinger finally cleared up some of this confusion, synonymising Acacia smallii and a number of other taxa under the nominate form of A. farnesiana, under which they also included all of the plants growing outside of the Americas. In the same paper, they recognised A. farnesiana var. guanacastensis from herbarium collections made by D. H. Janzen in 1976 in Guanacaste, Costa Rica. This taxon was later elevated to species status as A. guanacastensis by the same three in 2000 and later moved to Vachellia guanacastensis by Seigler and Ebinger in 2006. Acacia pinetorum was subsumed under A. farnesiana as A. farnesiana subsp. pinetorum in 2002 by Clarke, Seigler and Ebinger (rendering the nominate form A. farnesiana subsp. farnesiana). Seigler and Ebinger later reclassified this as Vachellia farnesiana var. pinetorum in 2005. Infraspecific diversity Acacia farnesiana var. guanacastensis is primarily distinguished by larger leaflets. It remains controversial; most taxonomic authorities in Mexico and Central America recognise this taxon as a full species under either A. guanacastensis or Vachellia guanacastensis, the Árboles nativos e introduciados de El Salvador of 2009 subsumed it under Acacia farnesiana. It is recognised as present in Costa Rica, El Salvador, Guatemala, Nicaragua, and the southern Gulf and southwestern regions of Mexico by the Kew World Checklist of Selected Plant Families (2018), but whether the taxon as recognised by the different authorities replaces Acacia farnesiana in Central America (but not the Caribbean or South America) or exists sympatrically remains unclear. This has implications for the classification of the extra-American distribution of A. farnesiana as the populations growing in Australia and the Philippines have recently (2017) been shown to derive from ancient Central American origins. Acacia pinetorum, the pineland acacia or pineland wattle, is also disputed. The International Legume Database and Information