520 BOTANY OF SIMPSON’S EXPEDITION. 
Plains, H. Engelmann). Stem covered with a light-gray bark, which is separated into many layers of loose shreds 
connected by smaller transverse fibres, and is readily torn off. Wood light, porous, pale-colored, with very many 
darker brown medullary rays, easily separating along the division of the annual rings. These rings, or layers, are from 
4-1 line in thickness, as stems of 14-2 inches diameter show about a dozen rings, and are consequently as many years 
old. The stems are rarely cylindrical, but mostly compressed, knotty, and variously twisted, and often stunted ; they 
are sometimes divided from the base, but oftener bear short and thick branches higher up. The annual branchlets are 
crowded along the older branches, 8-12 inches long, densely coated with a soft, white pubescence, and crowded with 
silvery-gray leaves, and bear toward their upper part and on the numerous short and erect lateral branchlets a profusion 
of small flower-heads, forming a spiked or contracted panicle, interspersed with short leaves. The leaves are flat, 
linear-lanceolate, entire or (the lower ones) rarely lobed, 1-2 or 2} lines wide and 14-2 inches long, the upper ones 
becoming smaller. The flower-heads are mostly sessile, or near *s so, hemispherical, hai 2 lines long and wide; 
outer scales of involucrum shorter, foliaceous, and canescent (sometimes the lowest ones larger than the flowers, and 
pointed) ; inner scales nearly as long as flowers, brownish, scarious, obtuse, cottony-fimbriate on the margins. The 
flowers are all perfect, usually 5, in some specimens as many as 8 in number, 1} lines long ; ovary glandular, and, 
when bruised, with the odor of wormwood. 
This is the “ Wild Sage” of the Upper Missouri (above the mouth of the Yellowstone) and the Yellow- [445] 
stone River, and of the Laramie Pi: ains, but it does not seem to occur west of the Rocky Mountains, as Torrey 
and Gray (/. c.) already state, and Nuttall (/. c.) must have confounded it with other species, when he contends that it 
is “still more abundant on the barren plains of the Columbia River,” and that it grows 6 to 8 or 12 feet high. 
ARTEMISIA TRIDENTATA, Nuttall in Trans. Amer. Phil. Soc. (n. ser.) 7, p. 398 ; Torrey & Gray, Fl. 2, p. 418.— 
Trunk, bark, and wood very similar to that of the last species, but trunk often larger, and usually even more twisted 
and knotty, with very numerous short and stunted branches, which are repeatedly divided into a great many smaller 
chlets ; ultimate annual branchlets fascicled, erect, only 3-6 inches long, canescent or silvery, very leafy at hase, 
rather naked upward, bearing strict, rather compact, paniculate spikes, seine of sessile or usually pedunculate 
spikelets or glomerules of 3 to 6 or 8 sessile heads. Leaves silvery-white on both surfaces, crowded at the base of the 
branches, and often fascicled on short or stunted sterile branches, narrowly wedge-shaped, 14-2 lines wide at the 
obtuse tridentate or trilobed end, narrowed down into a more or less distinct petiole; usually 3-6, rarely 8, lines long. 
Inflorescence interspersed with short and narrow, undivided, cuneate or spatulate obtuse leaves. Heads of flowers 
narrow, obovoid, nearly 14 lines long, not much more than half as wide, with short and obtuse, canescent, exterior 
es, and longer, scarious, interior scales, ciliate on the sides, Flowers in some specimens 3, in others often 4-5 in 
each head, all perfect, scarcely more than 1 line long; ovary quite glandular and with the odor of turpentine. 
This is the “ Wild Sage” of Utah, and, ean of the whole region west of the Rocky Mountains, where it 
seems to supplant the more eastern A. cana. Nuttall, who.first described it, calls it a shrub about a foot high, and as 
such it appears in the mountains of Colorado ; but in Utah it is the largest and most abundant species, usually 2-4 
feet high, rarely attaining a height of 6 feet, and then not straight, and with trunks of 3-6 inches in diameter ; some- 
times the smallest bushes have trunks fully as thick as the tallest ones, short and chunky. East of the mountains, in 
the range of A. cana, it ever remains an inconspicuous shrub, lost among the more common species. Near Camp 
Floyd specimens were collected bearing white tomentose excrescences of the size of a pea, or larger, undoubtedly galls 
caused by the sting of insects ; the same have been observed on this species in Colorado, 
The other species of Sims collected by the expedition were A. Canadensis, Michx., at Bridger’s Pass ; A. 
Ludoviciana, Nutt., at Sweetwater, Bridger’s Pass, Round Prairie, etc. ; A. dracunculoides, Pash; on the Sweetwater ; 
and A. frigida, Willd., on the Upper Sweetwater River. 
SARCOBATUS VERMICULATUS, Torrey in Emory’s Sonikt (1848), p. 149. Batis (2) vermiculata, Hooker, Flor. Bor.- 
Am. 2, p. 128 (1840). Sarcobatus Maximiliani, Nees in Pr. Maximil. Trav. Engl. ed. p. 518 (ex Torrey) ; Seubert in 
Bot. Zeitung, 1844, p. 753, cum tab.; Lindley in Hooker, Lond. Journ. Bot. iv. p. 1 (1845). Fremontia vermicu 
laris, Torrey in Fremont’s First Report, 1843, Rept. 1845, p. 95, and Fremont’s Second Report, 1845, : a1, [446] 
tab. 3. Sarcacanthus, Nuttall in Pl. Gambel. p. 184. Sarcobatus vermicularis, Torrey in Sitgr. Rep. p. 1 
Stansb. Rep. p. 394, in Bot. Whipple, p. 130.1— Pulpy Thorn or Pulpy-leaved Thorn of Lewis and pte Gre 
of the present travellers and settlers. 
This curious and important plant is found on the arid saline plains, principally on clayey soil, which in the wet 
is moist, and on the border of salt-lakes, often covering large patches, from below Fort Pierre on the Missouri 
(Dr. Hayden) to the Upper Platte River (Fremont, H. Engelmann), and Upper Canadian (Dr. James) east of the Rocky 
Mountains to the plains of the Columbia (Lewis and Clarke, Douglas, Fremont), Utah (Fremont, Stansbury) through the 
Basin to Carson Valley (H. Engelmann) and down to the Gila River (Emory). Though discovered and noticed b 
1 Compare 8. Watson’s Revision of the American Chenopodiacee in Proc. Am. Ac. Arts Sc. vol. ix. p. 82 (1875). 
