This BioProvince (as defined by Armen Takhtajan) comprises the Chaco or Gran Chaco and Southern Andean Yungas. Chacoan vegetation covers the vast plains of north-central Argentina, western Paraguay, southeast Bolivia and extends into Brazil along the a narrow strip parallel to the River Paraquay in Mato Grosso do Sul. This area represents a massive outwash plain built up from accumulations of Quaternary sediments derived from the eastern Andes. The underlying bedrock is largely made up of the Pre-Cambrian Brazilian Shield. The Yungas is a subtropical region spanning southwest Bolivia and northwest Argentina and possibly should be regarded as a bioprovince or sub-bioprovince in its own right. It is a rainy, forested area in a rugged terrain of deep valleys, gorges and sharp ridges, and represents mesic habitat lying between two drier habitats – the Chaco to the east and the higher Puna to the west. The climate varies, being wetter in the east, but much of the Chacoan area is characterised by mild, dry winters and hot, humid summers. This is one of the few areas in the World where the transition zone between tropic and temperate regions supports semiarid forest and woodland rather than desert. The flora includes many endemic or near endemic genera and a multitude of endemic species.
The following accounts for this BioProvince have been written or will be written with particular reference to endemic and locally important species. Accounts available are displayed in green or yellow. Those displayed in red are either in the pipeline or awaiting expert contributions.
|Endemic Vascular Plant Flora|