Varieties or subspecies:
Yucca angustissima ssp. kanabensis
Yucca angustissima ssp. avia
Yucca angustissima ssp. toftiae

Type location: BIGELOW, deserts of the Colorado River area, apparently from near the San Francisco Mts., near Picacho, Mohave Co., Arizona, in 1854, M 148375, 148376.

Distribution:
Mostly in open desert (Sagebrush vegetation), in sandy soil, and occasionally in open Pinyon-Juniper and Ponderosa Pine woods, SW Utah, N and central Arizona, NW New Mexico, in 1.000-2.550 m. Associated with Navajoa peeblesiana ssp. fickeisenii, Toumeya papyracantha, Sclerocactus parviflorus, Pediocactus (Utahia) sileri, Escobaria missouriensis ssp. navajoensis, various Echinocereus species, Opuntia species and Agave utahensis var. kaibabensis.

Short description of the species:
Plant: Acaulescent or with short prostate, 10 to 40 cm tall, single rosettes, or in clumps. Leaves: linear, plano-convex, 25 cm - 45 cm long,. 4 -15 mm wide bluish green, at basis 25 to 60 mm wide, edge of leaves white, yellow brown spine 3 to 7 mm long Inflorescence: upright or slightly bend racemen that are above the leaves, 50 to 150 cm tall (occasionally 180 cm!), scape it self is 30 to 40 cm long, rarely branched, stem greenish, reddish to purple, smooth or pubescent (with short hairs). Flower: pendulous (bell shaped) 45 to 55 mm long, white to cream, greenish-white or rose-purplish. Fruit: 35 to 50 mm long (57 mm), 22 to 30 mm thick. Seeds black, dull, 5 to 7 mm long.

Pictures:

Yucca angustissima near Peach Springs Arizona
Photo by Craig Howe ©2000-2005

My own plants:
#761    Yucca angustissima,  NARGS 95-5242, sown 1997.
#776    Yucca angustissima, Arizona, Peach Springs, 1700 m, fh 1178.44 sown 1997.
#777    Yucca angustissima, Utah, Zion Canyon area, mb 403 sown 1997.
#1045  Yucca angustissima, Arizona, Blue mtn, 1890 m., fh 1179.11 sown 1999.
#1046  Yucca angustissima, New Mexico, Mesa Gigante, 1850 m., fh 1179.46 sown 1999.

Hardiness:
I haven't had many experiments with this species yet, but I would think it would be OK if it's protected against moisture, or inside an unheated greenhouse.

Reference:
HOCHSTAETTER, Het geslacht Yucca (2), Succulenta, 78(1), 28-33, 1999
HOCHSTAETTER, Yucca (Agavaceae) CD-rom no. 3, 1999.
ENGELMANN ex TRELEASE, Ann.  Rept.  Mo.  Bot. Gard.  13: 58, tt. 23, fig. 1, 24, fig 1, 83, fig. 6, 93, fig. 1 (range map) (1902)
MCKELVEY, Yuccas southwest. U.S. 2:102-108 (1947) (Yucca angustissima)