The species of Stenanthium other than S. gramineum have at times been transferred to the segregate genus Stenanthella based on their racemose inflorescences, darker, campanulate flowers, and apically recurved tepals, leaving a monotypic Stenanthium with paniculate inflorescences, lighter colored, rotate flowers, and spreading tepals (P. A. Rydberg 1900). These differences are not sufficiently constant, however, to warrant the generic distinction (F. H. Utech 1987, 1987b). Among the melanthioid genera, Stenanthium shows greatest morphological similarities to Zigadenus Michaux (J. D. Ambrose 1975, 1980; S. J. Preece 1956; W. B. Zomlefer 1997b; W. B. Zomlefer et al. 2001). Stenathium gramineum and S. occidentale are occasionally cultivated as garden ornamentals.