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.
Shrub to 1.5 m tall Stem: usually growing just below soil surface, to 30 or 40 cm long. Leaves: evergreen, 30 cm - 0.8 m long, 2 - 7 cm wide, linear-elliptic, narrowing abruptly a into spine-like tip, non-toothed but with curly thread-like filaments separating from margin. Inflorescence: borne above the leaves on a 1 - 3 m long stalk, loosely branched (panicle), 0.75 - 1.5 m long, erect, cone-shaped, many-flowered. Flowers: yellowish white, 5 - 7 cm across, 2 - 3 cm wide, drooping, with six fleshy tepals, six stamens, and a pistil 1.5 - 3.8 cm long. Fruit: capsule-like, 2 - 5 cm long, 2 cm wide, cylindrical to oblong, erect, thick, breaking open from inner partitions (septicidal), containing many dull black and thin seeds 6 mm across.
Similar species: Yucca filamentosa can easily be identified in the Chicago Region by its evergreen, linear-elliptic leaves with spine-like tips and thread-like filaments along the margins.
Flowering: late June to early July
Habitat and ecology: Introduced from the southern United States, this species occasionally escapes from cultivation and is most often found along railroads or roadsides in sandy soil.
Occurence in the Chicago region: non-native
Notes: Yucca moths have a mutual relationship with members of this genus. The fragrance of the flowers draws the female moth to the flower's nectar at night. After feeding on the nectar, she rolls the flower's pollen into a ball and transports it to another flower. She then lays her eggs in the ovary of this flower and drops the pollen ball onto the stigma, making certain seeds will develop to feed her young. However, the larvae will only consume 20 to 40 percent of the seeds, leaving plenty of seeds to mature and disperse.
Etymology: Yucca is the Carribean name for manihot or cassava. Filamentosa means "having filaments or threads," referring to the stringy leaf edges.
Author: The Morton Arboretum
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.
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