Plants acaulescent or rarely caulescent, indistinctly arborescent, 1-4.6 m; rosettes usually small. Stems simple, 0-0.5 m. Leaf blade occasionally erect, proximal leaves often becoming reflexed near middle, lanceolate, flattened, abruptly narrowed and furrowed to apex, thin, widest near middle, 50-75 × 2-4 cm, usually soft and limp, scabrous, margins entire, long and curling, filiferous. Inflorescences paniculate, arising beyond rosettes, ovoid, 7.5-15 dm, glabrous; bracts erect; peduncle scapelike, 1-3 m, less than 2.5 cm diam. Flowers pendent; perianth globose; tepals distinct, nearly white, ovate, 5-7 × 2-3 cm, glabrous, apex short-acuminate; filaments shorter than pistil; pistil 1.5-3.8 cm; stigmas lobed. Fruits erect, capsular, dehiscent, oblong, 3.8-5 × 2 cm, dehiscence septicidal. Seeds dull black, thin, 6 mm diam. Flowering mid spring--early summer. Sandy soil; Ala., Fla., Ga., La., Md., Miss., N.C., S.C., Tenn., Va., W.Va. Yucca filamentosa is often cultivated and has become naturalized in some areas beyond its native range. Varieties that have been described are rarely recognized in recent literature. Yucca filamentosa and Y. flaccida are very closely related and perhaps are not distinct species.
Caudex short, to 3 or 4 dm; lvs numerous, stiff, linear- elliptic to linear-spatulate, to 8 dm, 2-7 cm wide, fibrous along the margins, abruptly prolonged into a short stout spine, ±scabrous; infl paniculate, many-fld, rising to 1-3 m, its base elevated well above the lvs; tep 5-7 נ2-3 cm, rounded above, short-acuminate; style nearly 1 cm; stigmas slender; fr thick- cylindric, 2-4 cm; seeds 6 mm. Sand-dunes and dry sandy soil, especially near the coast; Md. to Fla. and La.; often escaped from cult. farther n. June-Sept. (Y. concava; Y. smalliana)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.