A survey of 20 km2 of species-rich kwongan (sclerophyllous shrubland or sandplain vegetation) is reported, A total of 429 vascular plant species were found, of which 338 were recorded at the eighty-seven systematically located 0.1 ha releves, Five vegetation units were defined following analysis of the site floristics data. Small but distinctive suites of species (totalling 26% of recorded species) characterized a gradient in soils from the sands and gravels of the lateritic uplands, through the deep sands of the dune sequence, to the clays of the winter-wet depressions. However the soils-related axis in the ordinations accounted for only ca. 6% of the variability in the data, indicating the complexity of the vegetation environment interactions. Species richness was greatest in a zone of apparent overlap between the lateritic group of species and those of the deep sand areas. The winter-wet areas were poorest in species. The distributions of the floristically defined vegetation units did not closely parallel those of physiognomic units defined by interpretation of air photos. Structural dominance was negligible in all but the winter-wet areas and the few dominants appeared poorly correlated with other species and with the physical environment. Comparisons are made with areas of similar vegetation elsewhere in Australia and in South Africa.