Sierra Blanca Yucca 



159 



III. SIERRA BLANCA YUCCA 



GENUS SAMUELA TRELEASE 



Species Samuela Faxoniana Trelease 



Yiccca macrocarpa Sargent, not Engelmann 



Yucca Faxoniana Sargent 



]NOWN only from the vicinity of Sierra Blanca in western Texas, this 

 Yucca-like plant probably extends into adjacent Mexico. Its maxi- 

 mum height is about 12 meters, with a trunk diameter of 6 dm. 

 The trunk is usually simple, seldom having a few short branches. 



The young plants are densely covered with numerous erect or radiating living 



leaves; later the base is covered by a 



thatch-like covering of reflexed dead 



leaves; on old trees the rind is exposed 



at the base. The rind is about 8 mm, 



thick, dark reddish brown, and scaly. 



The leaves are dark green and smooth, 



linear-oblong, i to 1.25 m. long, stiff and 



firm, abRiptly narrowed just above the 



thickened, shining red clasping base 



which is often 1.5 dm. broad, widest at 



or above the middle and sHghtly con- 

 cave toward the apex, which is armed 



with a very sharp, dark tip; the margin 



separates into grayish threads, which, 



with the exception of a few coarse fibers 



near the apex, eventually peel back- 

 ward and form a persistent tangled 



Fig. 119. Sierra Blanca Yucca. 



mass at the base of the leaf. The flowers, which appear in spring, are in short- 

 stalked, broadly conic loosely-branched panicles with persistent white bracts; they 

 are drooping on long stalks, 5 to 10 cm. across; the perianth is funnelform, of 

 6 parts, which are broadly lanceolate, sharp-pointed, and cur\Td inwardly at the 

 apex, united at the base into a tube about 8 mm. long, those of the outer series 

 narrower; stamens 6, their filaments shorter than the ovary, club-shaped, hair}', 

 and curved outward; anthers arrow-shaped and horizontal; ovary sessile, narrowly 

 oblong, ridged, yellowish, longer than and narrowed into the slender, grooved style; 

 stigma irregularly 6-lobed. The fruit, which ripens in early summer, is indehiscent, 

 2.5 to 7.5 cm. long, fleshy, pendent, oblong-ovoid, scarcely angled, beaked at the 

 apex, dark yellow and shining, becoming black, the flesh dr\'ish, bitter and sweet; 

 seeds rounded triangular, flat but thick, about 6 mm. long and half as thick, not 

 margined. 



