Included here is a small area of the Chaco or Gran Chaco. It 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. The climate varies, being much dryer in the west. However, it is one of the few areas in the World where the transition zone between tropic and temperate regions supports semi-arid vegetation rather than complete desert.

Chacoan Cactus Scrub

Cactus scrub dominated by the monotypic genus Stetsonia (Cactaceae) endemic to the Chaco is common in the western Chaco, but moving east it becomes increasingly rare. Stetsonia coryne is a large candelabra-like species that can become particularly dominant in strongly saline soils where much of the ground is either bare or covered in mosses and the clubmoss Selaginella sellowii.


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