LILIACE. SILVA OF NORTH AMERICA. 19 
YUCCA ARBORESCENS. 
Joshua Tree. 
LEAVES concave above the middle, blue-green, sharply serrate. 
Yucca arborescens, Trelease, Rep. Missouri Bot. Gard. Nat. ix. 141, 351.— Watson, Proc. Am. Acad. xiv. 
ili. 163, t. 5, 49 (1893). — Coville, Contrib. U. S. Nat. 252. — Baker, Jour. Linn. Soc. xviii. 221.— Brewer & 
Herb. iv. 201, t. (Bot. Death Valley Exped.). Watson, Bot. Cal. ii. 164.— Sargent, Forest Trees N. 
Yucca Draconis, var. arborescens, Torrey, Pacific R. R. Am. 10th Census U. S. ix. 218.— Gard. Chron. ser. 3, i. 
Fep. iv. pt. v. 147 (1857). 772, {. 145. —S. B. Parish, Garden and Forest, iv. 135; 
Yucca brevifolia, Engelmann, Watson King’s Rep. v. 496 Zoé, iv. 349.—Trelease, Rep. Missouri Bot. Gard. iv. 
(1871); Trans. St. Louis Acad. iii. 47. — Parry, Am. 193, t. 6-9, 21. 
A tree, from thirty to forty feet tall, with stout tough roots descending deeply into the soil from a 
broad thick basal disk from which the trunk rises abruptly. Until the stem attains a height of eight 
or ten feet it is simple and clothed to the ground with leaves which are erect until after the appearance 
of the first panicle of flowers, when they spread at right angles, and, finally becoming reflexed, do not 
disappear for many years; after flowering the stem forms two or three branches, ultimately becomes 
two or three feet in diameter, covered, like the short stout limbs, with gray bark from an inch to 
an inch and a half in thickness, and deeply divided into oblong plates frequently two inches in length, 
and bears a broad and often symmetrical head formed by the continued forking of the branches at the 
base of the terminal flower-clusters. The rigid leaves, which are crowded in densely imbricated clusters 
at the end of the branches, are lanceolate, and taper gradually or rarely are slightly contracted above 
the bright red-brown lustrous base, which is from an inch and a half to two inches wide; they are from 
five to eight, or rarely on vigorous young plants ten or twelve inches in length, and from one quarter 
to one half of an inch in width; they are concave above the middle, flat or only slightly concave 
toward the base, tipped with sharp gradually tapering dark red-brown points from one half to three 
quarters of an inch long, bluish green and glaucous, and smooth or slightly roughened, with thin 
yellow margins armed with sharp minute teeth. The flowers appear from March until the beginning of 
May, the creamy white closely imbricated bracts of the panicle, which are often flushed with purple at 
the apex, forming before its appearance a conspicuous conical cone-like bud eight or ten inches in 
length. The panicle is nearly sessile, pubescent, densely flowered, fifteen or sixteen inches long and 
about eight inches broad, with a stout rachis an inch and a half thick at the base, and gradually 
tapering to the apex, and short stout branches; the lower bracts are sterile, and, although rather 
shorter, resemble the leaves except at the base, which is oblong, leathery, creamy white, about two and 
a half inches long and an inch and a quarter broad; by the gradual lengthening of the wide base and 
the shortening of the green leaf-like tip, the inner bracts, from which the branches of the inflorescence 
spring, are oblong-ovate or oblong-obovate, acuminate, leathery, creamy white, and seven or eight 
inches long, and from one to two inches broad, gradually decreasing im size toward the apex of the 
panicle, those at the base of the upper branches being not more than three inches in length ; the lowest 
fertile bract bears one or two flowers in its axil; and at the base of each branch are usually two solitary 
flowers, while the rest of its flowers, eight or ten in number, are arranged above its middle, each in the 
axis of a creamy white bract, the bracts decreasing im size toward the end of the branch, the largest 
being about an inch and a half long and a quarter of an inch broad, and the smallest not more than 
half that size. The flowers, which vary from globose to oblong in shape and from one to two inches in 
length, are greenish white, waxy, and dull or lustrous, and emit a strong and rather disagreeable odor ; 
