On the basis of quantitative vegetational sampling, climatic data, and soil analysis, the basin sagebrush association of Clements is di-divided into 2 zones: sagebrush and shadscale. The shadscale zone lies between the sagebrush zone on the n. and the creosote bush zone on the s. in the very arid rain-shadow region e. of the Sierra Nevada. Its areal distribution in relation to the 2 other desert zones in Nevada and eastern California is shown by map. As brought out by quantitative sampling, the vegetation of the matrix community of the zone is dominated by Atriplex confer-tifolia, Artemisia spinescens, Sarcobatus baileyi, Lycium cooperi, and other small, spiny, microphyll shrubs. This community occurs under warmer and drier conditions than the sagebrush zone but in a region too cold for creosote bush vegetation. In the north, the zone is restricted principally to the valleys while in the south, it is found mainly on ridges and steep hillsides. The zonal soils under shadscale vegetation are gray desert soils. In the northern valleys, these soils may show mild concns. of salt in the subsoil but in the drier portions of the zone where shadscale vegetation occurs on well-drained slopes, the subsoil is usually no more saline than sagebrush subsoils. Embedded in the matrix of the zone are edaphic communities which are characteristic of intra-zonal or azonal soils. While each of the several dominant spp. has its own environmental tolerances and range; they occur together in this region to produce a distinct vegetation zone with particular biotic characteristics.