Yucca rostrata

Plants solitary or forming colonies of rosettes, caulescent, arborescent, 2.5-3.6 m, not including inflorescence, 1.8-3.2 dm diam; rosettes each with more than 100 leaves. Stems 1-several, erect, mostly simple, occasionally 1-3-branched. Leaf blade linear, often twisted, flat to concavo-convex, widest considerably beyond middle, 25-60 × 1.2-1.7 cm, glaucous, smooth, margins minutely denticulate, lemon yellow, hyaline, apex spinose, spine tipped. Inflorescences paniculate, arising just within or beyond rosettes, ovoid, 3-10 dm; branches up to 3.8 dm; bracts erect; peduncle sometimes scapelike, 0.3-1 m, less than 2.5 cm diam., glabrous or glabrescent. Flowers pendent; perianth globose to campanulate; tepals distinct, white, narrowly ovate, 4.2-5.2 × 1.1-2 cm, apex sharply acuminate; filaments 1.7-2 cm; pistil 2.5-3.5 cm; style white, 6-14 mm; stigmas lobed. Fruits erect, capsular, dehiscent, ovoid to ellipsoid, rarely constricted, 4-7 × 1.8-2.5 cm, dehiscence septicidal.

Flowering spring. Rocky mountain slopes, canyon bottoms; 700 m; Tex.; n Mexico (Coahuila).

In the United States, Yucca rostrata is restricted to Brewster County, Texas. It is closely related to Y. thompsoniana (K. H. Clary 1997), which is perhaps just a northern variant of this species.