Yucca thompsoniana


Rep. (Annual) Missouri Bot. Gard. 22: 101, plates 104–107. 1911.

Common names: Thompson yucca bayoneta
Treatment appears in FNA Volume 26. Treatment on page 430. Mentioned on page 425, 431, 432.

Plants solitary or forming colonies of rosettes, caulescent, arborescent, mostly asymmetrical, 0.7–2.5 m, not including inflorescence, to 30 cm diam.; rosettes each with more than 100 leaves. Stems 1, erect, 1–3-branched. Leaf blade linear, flat or concavo-convex or slightly keeled, widest at or above middle, 20–30(–45) × 0.7–1.2 cm, flexible, ± scabrous adaxially and abaxially, margins denticulate, yellow or orangish red, corneous, apex sharp-pointed. Inflorescences paniculate, racemose at apex, arising beyond rosettes, 5–8 dm; branches to 2 dm; bracts erect, 10–13(–17) cm; peduncle sometimes scapelike, (0.3–)0.4–0.7 m, 1.3–2 cm diam., glabrous or glabrescent. Flowers pendent; perianth globose to campanulate; tepals distinct, white, narrowly elliptic, 3.5–6.5 × 1.2–3.5 cm, glossy, apex sharply acuminate; filaments 1.7–3.3 cm; pistil 2.5–3.8 × 0.4–0.8 cm; style white, 6–18 mm; stigmas lobed. Fruits erect, capsular, dehiscent, ovoid, rarely constricted, 3.5–7 × 2–2.5 cm, dehiscence septicidal. Seeds dull black, thin, 6–8 mm diam.

Phenology: Flowering spring.
Habitat: Rocky slopes and hills
Elevation: 200–1400 m


V26 884-distribution-map.jpg

Tex., n Mexico (Chihuahua, Coahuila).


Yucca thompsoniana occurs in the trans-Pecos area of Texas. J. M. Webber (1953) characterized it as a dwarflike form of Y. rostrata, and the differences are perhaps not sufficient to merit separate recognition. Webber also suggested that it may hybridize with Y. reverchonii.

Selected References


Lower Taxa