116 



TREES OF NORTH AMERICA 



enlarged base, unbranched or divided into several short branches, and covered above by a 

 thick thatch of the pendant dead leaves of many seasons; frequently smaller and until ten or 

 twelve years old clothed from the ground with erect living leaves. Bark near the base of old 

 trees dark reddish brown, $'-' thick, broken on the surface into small thin loose scales. 

 Distribution. Common on the high desert plateau of southwestern Texas. 



7. Yucca brevifolia Engelm. Joshua Tree. 



Yucca arbor escens Trel. 



Leaves 5'-8' or on young plants rarely 10'-12' long, |'-|' wide, rigid, crowded in dense 

 clusters, lanceolate, gradually tapering from the bright red-brown lustrous base, bluish 

 green and glaucous, smooth or slightly roughened, concave above the middle, with a sharp 

 dark brown tip, and thin yellow margins armed with sharp minute teeth; persistent 



Fig. 112 



for many years. Flowers appearing from March until the beginning of May, the creamy 

 white closely imbricated bracts of the nearly sessile pubescent panicle forming before 

 its appearance a conspicuous cone-like bud 8' or 10' long; perianth globose to oblong, 

 l'-2' long, greenish white, waxy, dull or lustrous, its segments slightly united at the base, 

 keeled on the back, thin below the middle, gradually thickened upward into the concave 

 incurved rounded tip, those of the outer rank rather broader, thicker, and more prominently 

 keeled than those of the inner rank, glabrous or pubescent; stamens about half as long as 

 the ovary, with filaments villose-papillate from the base; ovary conic, 3-lobed above the 

 middle, bright green, with narrow slightly developed septal nectar-glands, and a sessile 

 nearly equally 6-lobed stigma. Fruit ripening in May or June, spreading or more or less 

 pendant at maturity, oblong-ovoid, acute, slightly 3-angled, 2'-4' long, \\'-% thick, light 

 red or yellow-brown, the outer coat becoming dry and spongy at maturity; seeds nearly 

 \' long, rather less than ^' thick, with a broad well-developed margin to the rim, and a 

 large conspicuous hilum. 



A tree, 30-40 high, with a trunk 2-3 in diameter, rising abruptly from a broad thick- 

 basal disk, thick tough roots descending deeply into the soil, and stout branches spreading 

 into a broad, often symmetrical head formed by the continued forking of the branches at 

 the base of the terminal flower-clusters; the stem until 8-10 high simple and clothed to the 

 ground with leaves erect until after the appearance of the first flowers, then spreading at 

 right angles and finally becoming reflexed. Bark I'-l^' thick, deeply divided into oblong 

 plates frequently 2 long. Wood light, soft, spongy, difficult to work, light brown or 

 nearly white; sometimes cut into thin layers and used as wrapping material or manufac- 

 tured into boxes and other small articles. The seeds are gathered and eaten by Indians. 



