This ranges widely across east-central states, but it is centered in Appalachian and Ozarkian regions. S. gramineum is a generally uncommon to endangered species of thin woods and openings on wet to dry sites, usually with medium acid soils. In Ky. it survives mostly in scattered remnants of thin swampy woods and seasonally wet meadows, including some rights-of-way. Its distribution in the state is highly fragmented, and several populations have disappeared since 1950; similar declines have been documented in s. Ill. (Edgin 2004) and elsewhere (NS: Natural Heritage databases). Varieties are combined here, as in most recent treatments (e.g. Cr, FNA 26), but further study is warranted (W). Colls. from CALD, FAYE, FLEM, HART, HOPK, ROCK and ROWA are referable to var. robusta (S. Wats.) Fern., which may be typical of deeper swamps or relatively fertile soils. Colls. from LAUR, MCRE, PULA and WHIT are referable to var. micranthum Fern., which may be typical of streamhead seeps on infertile soils of the Cumberland Plateau. The latter appears distinctive. It needs to be compared with S. diffusa Wofford, which was recently described from sandstone rockhouses of adjacent Tenn. (Wofford 2006) and is expected in Ky.