Synonyms:
Yucca rupicola sensu Trelease, in Rep. Missouri Bot. Gard. 13: 1902, t. 39, 2 figs., and in part as to range.

Type location:
Just north of Ranger, Eastland Co., Texas.

Distribution:
In Texas, Dallas, Waco, Killeen Region, at 165 - 300 m.

Short description of the species:
Plants acaulescent, forming small or larger open clumps of rosettes of with few leaves. Leaves bluish, waxy, 20 - 35 cm long, 3 cm wide, margin of the leaves dark olive-green with short sharp "teeth's". Inflorescens 100 to 250 cm tall (occasionally 400 cm l. Scape held high above the leaves 60 to 130 cm long (occasionally up to 300 cm long!). Branchlets 10 to 20 cm long. Flowers campanulate (bell shaped), 5 to 6,5 cm long, white to greenish. Fruit 4 to 6 cm long, 1,5 to 3 cm thick. Seeds black dull, quite small 0,4 to 0,6 x 0,2 to 0,3 cm.

Leaf of Yucca pallida. Photo by Benny Moeller Jensen ©2000-2005

Notes:
The new growth is quite distinctive from Yucca rupicola while the leaf grows as a spike in the center of the rosette and dos not loosen it from the "spike" until it's almost grown to it's full length. In Yucca rupicola the leaf starts to grow from way down in the rosette (almost like on a Bromelia!!).

Yucca pallida is related to:
Yucca reverchoni
Yucca rostrata
Yucca rupicola
Yucca thompsoniana
Yucca cernua, status not sure, maybe a natural hybrid with genes from Yucca rupicola or Yucca pallida?

Hardiness:
Yucca pallida is quite hardy if it can be kept dry during the winter, I have a plant that are grown inside in an unheated greenhouse, and the plant really look healthy. Another plant is grown in a raised bed, that are protected against winter moisture from October to May, this plant does OK in mild winters, but in very cold and long winters the rosettes are killed, but then new rosettes starts from the rhizomes.

My own plants:

#339A Yucca pallida, Texas, Mills Co.,
            grown in a pot that are stored inside the unheated greenhouse during the winter.
            Sown 1992, seeds from Mesa Garden #1977.86
#339B Yucca pallida, Texas, Mills Co.,
           grown in a pot that are stored inside the unheated greenhouse during the winter.
           Sown 1992, seeds from Mesa Garden #1977.86
#339C Yucca pallida, Texas, Mills Co., Grown inside the unheated greenhouse.
            Sown 1992, seeds from Mesa Garden #1977.86
#339D Yucca pallida, Texas, Mills Co.,
            Grown in a protected bed, outside,
            This is OK during mild winters, but in very cold winters the rosettes are killed!
            Sown 1992, seeds from Mesa Garden #1977.86

Pictures:
 

#339C Yucca pallida, Texas, Mills Co., Grown inside the unheated greenhouse. Photo taken March 12th. 2000. Photo by Benny Moeller Jensen ©2000	#339C Yucca pallida, Texas, Mills Co., Grown inside the unheated greenhouse. The same plantas above is now in bud, June 14th 2001 Photo by Benny Moeller Jensen ©2001	#339D Yucca pallida, Texas, Mills Co., Grown in a protected bed, outside. Photo taken July 2th. 2000. Photo by Benny Moeller Jensen ©2000	Yucca pallida Grown in Alexander Heim's garden in his Greece. Copyright 2007 Alexander Heim.

If you have a photo of a flowering Yucca pallida, or a photo from habitat, would I be very happy if I may use it! Let me know.

Reference:
HOCHSTAETTER, F., Succulenta, Netherlands, Vol. 78 no. 5, 207-217, Yucca (Agavaceae) part 5.
HOCHSTAETTER, F; (2000), YUCCA (vol. I): 24-26 (Yucca pallida)
MCKELVEY, Yuccas of the S.W.U.S, vol. 2 (1947), 57 ff.
TRELEASE in Rep. Missouri Bot. Gard. 13: 1902, as to t. 39, 2 figs., and in part as to range.
The Flora of Texas Consortium Vascular Plants Endemic to Texas