Narrowleaf Yucca

Our treatment of Yucca angustissima reflects the concepts of J. L. Reveal (1977c). Each variety is well isolated geographically, but they overlap with one another morphologically. S. L. Welsh et al. (1993) treated the taxa in this complex at species level, with the exception of Y. angustissima var. aria, considered a high-altitude extreme of the typical variety. K. H. Clary (1997) presented DNA evidence that supports Welsh et al.’s treatment of this complex, in that Y. angustissima, Y. kanabensis, and Y. toftiae sort out distinctly from one another in her consensus tree. However, Welsh et al. indicated significant intergradation among these taxa, which makes their recognition at varietal rank seem most appropriate.

Plants solitary or forming small to large colonies of rosettes, acaulescent or rarely caulescent, to 3 m diam.; rosettes usually small. Stems procumbent, 0.1–0.4 m, or erect, 1–2 m. Leaf blade rigidly spreading, including distal leaves, linear, lanceolate, concavo-convex, or plano-keeled, widest near middle, 20–80(–150) × 0.4–2 cm, rigid or flexible, not glaucous, margins entire, becoming filiferous, white, becoming brownish, gray, or green, apex long-acuminate, spinose, spine acicular, short, 3–7 mm. Inflorescences racemose, occasionally paniculate proximally, arising well beyond rosettes, (4–)8–20 dm, glabrous or finely pubescent; branches, when present, 0.5–1 dm; bracts erect, linear, proximal 10–20 × 1–2 cm, distal 3–8 × 1–2 cm; peduncle scapelike, 0.3–2.5 m, 1–2 cm diam. Flowers pendent, 3–5.5(–6.5) cm; perianth campanulate to globose; tepals distinct, white to cream or greenish white, often tinged pink or brown, broad to narrowly elliptic to lanceolate-elliptic or orbiculate, 3–6.5 × 1.3–2.5 cm; filaments 0.7–2.8 cm; anthers 3.2–6 mm; pistil 1.5–3.5 cm; style white to pale green, 3–10(–13) mm; stigmas lobed. Fruits erect, capsular, dehiscent, moderately to deeply constricted, 3.5–7.5 × 2–3 cm, dehiscence septicidal. Seeds dull black, thin, 7–9 × 5–7 mm.

Yucca angustissima, the narrowleaf yucca, is a plant in the family Agavaceae, known as the "narrow-leaved yucca." It is native to Arizona, New Mexico, Colorado and Utah, but grown elsewhere as an ornamental.

Yucca angustissima is a low-lying species forming colonies of basal rosettes up to 3 m (10 feet) in diameter. Leaves are long and thin, up to 150 cm long but rarely more than 2 cm across. Flowers are white to cream or greenish-white, pendant, borne in racemes on stalks up to 2 m (7 feet) tall. Fruit is a dry capsule with black seeds.

Yucca angustissima is relatively abundant, and although it has local threats, its population appears to be stable overall.