This virtually monotypic genus is a distinct relative of Melica; 2n = 20. Typical purpurascens is widespread across boreal North America (FNA 24), usually in somewhat mesic woods. Closely related plants (known as ssp. callosa) are known in East Asia (Kowano & Koyama 1964). S. purpurascens is rare in unglaciated regions of eastern states. In Ky. it is known only from a remarkable disjunct cluster of sites along the Palisades of Ky. Rv. (from Boone Creek to Shaker Creek), where it occurs on narrow points with rocky ledges in thin subxeric to xeric woods.