Yucca whipplei ssp. caespitosa (Jones) HAINES, Madroño 41(6): 43, "1940" (1941)

Synonyms:
Yucca whipplei var. caespitosa Jones, M., West. Bot Contrib. 15: 59, 1929. (in part)

Type location:
Cactus Flat in Cushenbury Canyon, San Bernardino Co., California.

Distribution:
Desert woodland on southern and western slopes, often growing with Juniperus californica, at an altitude of 500 to 1200 m. it's to be found in California from Arrastre Creek in San Bernardino Co., along the western  border of Mojave Desert to the region of Walker Pass.

Short description of the species:
Plants acaulescent, Caespitose (making offsets by rhizomes, plants with op over 100 rosettes has been seen!), Monocarpic, (the single rosettes dying after flowering). Rosettes with 25 to 115 leaves. Leaves, bluish, 20 - 50 cm long, up to 1 to 2 cm wide, margin of the leaves corneous and finely serrulate (with very small teeth), has a very sharp spine at the tip of the leaves, the backside of the leaves scabrous (rough). Inflorescence one or many flowering rosettes from each group, paniculate, 120 to 400 cm tall. Scape held high above the leaves  45 to 180 cm long. Flowers campanulate (bell shaped) wide open, 2 to 6,5 cm long, white or with a purple tinge. Fruit 3 to 5 cm long, 1,5 to 3 cm thick, rarely constricted. Seeds black, shiny, 0,6 to 0,7 x 0,8 cm, with marginal wing

Seeds of Yucca whipplei ssp. caespitosa, California, Mojave Ranges, 1070 m., fh 1179.59, the seeds were sown 2000.
©1999-2005 Benny Moeller Jensen

Hardiness:
I have not had any experience with this species yet.
David J. Ferguson have seen this species growing with Artemisia tridentata, Pinus ponderosa, Pinus monophylla, Pseudotsuga macrocarpa, (also known as big-cone douglas-fir.), Juniperus californica, etc. near the Devil's Punch Bowl northeast of Los Angeles. This location often has a snowpack for long periods in the winter, and he suspect that these plants may make it into USDA Zone 6 locations (????).

Pictures:
I do not have any pictures of Yucca whipplei ssp. caespitosa if you have a picture I may use please let me know.

Notes:
1.         According to many authors this subspecies is "just" a natural variation of Yucca whipplei.

2.        Some authors place Yucca whipplei and it's subspecies in the Genus Hesperoyucca. One of the reasons to this is that the seedlings form a distinct bulb which no other Yucca does. another reason cold also be that Yucca whipplei and it's subspecies are pollinated by another species of Yucca moth which only do feed on Yucca whipplei!

Reference:

CLARY, Karen H., (http://www.agavaceae.com/botanik/pflanzen/botanzeige_scan_en.asp?gnr=220&scan=22190&cat=5&name=Hesperoyucca%C2%A0newberryi)
HAINES (1940) Madroño 41(6): 43, "1940" (1941) (Yucca whippleissp. caespitosa Haines)
HOCHSTÄTTER, F; (2000), YUCCA (vol. I): 19-20 (Yucca whipplei ssp. caespitosa)
MCKELVEY (1947)  Yuccas southwest. U.S. 2: 23-49 (1947) (Yucca whipplei)
JONES, M. (1929) West. Bot. Contrib. 15: 59. 1929 (Yucca whipplei var. caespitosa M. Jones)
THIEDE, J., Illustrated handbook of succulent plants vol. 1. (Monocotyledons (Eggli ed.)): 85-87, 2002. (Hesperoyucca whipplei).
WEBBER (1953) Agric. Monograph U.S.D.A. 17:34 (1953) (Yucca whipplei var. caespitosa M. Jones)