A small-scale mosaic of miombo woodlands and open, seasonally inundated grasslands is a typical aspect of the Zambezian phytochorion that extends into the eastern and central parts of Angola. The grasslands are home to so-called ‘underground trees’ or geoxylic suffrutices, a life form with massive underground wooden structures. Some (but not all) of the geoxylic suffrutices occur also in open woodland types. These iconic dwarf shrubs evolved in many plant families under similar environmental pressures, converting the Zambezian phytochorion into a unique evolutionary laboratory. In this chapter we assemble the current knowledge on distribution, diversity, ecology and evolutionary history of geoxylic suffrutices and suffrutex-grasslands in Angola and highlight their conservation values and challenges.  Keywords: Endemism, Geoxyles, Miombo, Phytochorion, Underground forests, Vegetation.