Plants solitary, caulescent, shorter than 3 m. Stems 1, simple, unbranched, shorter than 2 m. Leaf blade erect to reflexing with age, bluish-glaucous or green to yellow-green, thin, flat to conduplicate, flexible, margins entire or occasionally filiferous with slender fibers, brown to grayish, smooth. Inflorescences erect, paniculate, somewhat open, arising 1/4-1/2 within rosettes, elongate-ovoid, to 8 dm, sparsely pubescent. Flowers pendent, 3.5 cm; perianth ovoid; tepals distinct, or barely connate basally, white, ovate-lanceolate to lanceolate, ca. 3 × 1.4 cm; filaments ca. 1.5 cm, glabrous; pistil 1.5-4 cm; ovary ca. 2.5 cm. Fruits becoming pendent, baccate, indehiscent, 6-12.5 × 2.5-3.8 cm, fleshy, succulent. Seeds gray, 7-10 mm diam., 5-8 mm thick.
Flowering in summer with rains. Madrean pine-oak forest; 1400--1600 m; Ariz.; Mexico (Chihuahua, Sonora).
Yucca madrensis is closely related to Y. jaliscensis to the south and the Y. schottii complex to the north. We follow L. W. Lenz and M. A. Hanson (2000b), who have determined that plants with long, wide, flexible, blue leaves that are now usually identified as Y. schottii Engelmann (not congruent with Engelmann´s original description) are more correctly referred to Y. madrensis. Lenz and Hanson further suggested that what is now called Y. schottii represents a hybrid complex among Y. baccata, Y. elata, and Y. madrensis. This putative hybridization is conjectural, and without firm evidence we are uncertain as to the appropriate disposition of the name Y. schottii. We are somewhat skeptical of the potential for crosses between baccate species (Y. baccata and Y. madrensis) and capsular species (Y. elata).
Common Name: Unknown
Duration: Perennial
Nativity: Native
Lifeform: Succulent
General: Solitary, caulescent plants, shorter than 3 m. Stems simple, unbranched, shorter than 2 m.
Leaves: Blade erect to reflexing with age, bluish-glaucous or green to yellow-green, thin, flat to conduplicate, flexible; margins entire, rarely with marginal fibers, brown to grayish.
Flowers: Erect paniculate, open, comes from quarter to half within rosettes, elongate-ovoid to 8 dm, sparsely pubescent; pendant flowers, 3.5 cm, ovoid perianth, distinct tepals, or barely connate at base; white.
Fruits: Becoming pendant, banana like, indehiscent, 6-12.5 by 2.5-3.8 cm, fleshy, succulent.
Ecology: Found on slopes in Madrean pine-oak forests from 4,000-7,000 ft (1219-2134 m); flowers in late summer and fall with the rains.
Notes: This species emerges from discussion surrounding what formerly was Y. schottii. The phylogenetics suggest that Y. madrensis is the most accurate name for that species, following FNA and Lenz and Hanson 2000. Easy to distinguish by its community associations in the higher elevation pine-oak woodlands and the lack of curling fibers along the margin of leaves.
Ethnobotany: Uncertain; no documented usage, but given the wide variety of uses of other species in this genera.
Etymology: Yucca comes from Haitian for uuca, or manihot, because young inflorescences are sometimes roasted for food, while madriensis refers to the Sierra Madre.
Synonyms: Yucca schottii
Editor: SBuckley, 2010
