Enum. Pl. 4: 189. 1843
Herbs, perennial, from tunicate bulbs and reduced rhizomes; roots fibrous. Stems simple, mostly with 2–3 reduced bracts, glabrous. Leaves mostly basal, reduced distally, spiral, arching downward, sheathing proximally; blade narrowly linear to oblanceolate, strap-shaped, glabrous, apex acuminate or obtuse. Inflorescences terminal, racemose or paniculate, open, bracteate, glabrous. Flowers: proximalmost usually bisexual, distalmost staminate; perianth tubular-campanulate or rotate; tepals persistent, 6, distinct or weakly connate basally, glandular or not, oblong-lanceolate or lanceolate, equal to subequal, apex acute to acuminate; claws absent; tepal glands, when present, 2-lobed, adaxial; stamens 6, distinct or connate basally, equal or subequal; filaments lanceolate; anthers basifixed, 1-locular, obcordate-reniform; pollen sacs apically confluent, extrorse, opening into peltate disc; ovary superior to half-inferior, 3-locular proximally, 1-locular distal to ovules; septal nectaries absent; styles persistent, 3, spreading to recurved, distinct; stigmas minute. Fruits capsular, deeply 3-lobed, membranous, slenderly 3-beaked, dehiscence septicidal, then adaxially loculicidal. Seeds 3–4 per locule, brown to brownish black, narrowly oblong or ellipsoid to lanceoloid, flat, angled to winged. x = 8, 10.
North America (including Mexico), e Asia.
Species 4 (2 in the flora).
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.
Utech, F. H. 1987. Biosystematic studies in Stenanthium (Liliaceae: Veratreae). I. Floral morphology, floral vascular anatomy, geography and taxonomy of S. occidentale A. Gray. Ann. Carnegie Mus. 56: 113–135.
|1||Stems 1.5–4.5(–6) dm; leaves 15–30 cm; perianth tubular-campanulate; tepals greenish to brownish purple, 10–20 mm, recurved distally, apex gradually acuminate; w North America.||Stenanthium occidentale|
|1||Stems 5–20 dm; leaves 20–70 cm; perianth rotate; tepals white to greenish yellow, 4–10 mm, not recurved distally, apex acute to narrowly acuminate; e North America.||Stenanthium gramineum|