i i es ali ee el eal 
ARTEMISIA COM POSIT A 367 
and close tomentum. Heads homogamous, the flowers all her- 
-‘maphrodite and fertile Receptacle not hairy. 
* Heads solitary in the axils, surpassed by the rigid leaves. 
A. rigida Gray Proc Am. Acad. xix, 49. ‘‘ A span toa foot high from a 
thick woody base or short stem, producing a profusion of rigid and slender 
rather simple fastigiate branches, leafy to the very top: leaves also rigid, 
silvery-canescent, filiform-linear, 38-5 parted or cleft, or some of the upper 
and fascicled ones entire (even the lower rarely inch long), most of them 
subtending a sessile head: involucre oblong to campanulate, 5-12-flowered, 
less than 2 lines long; bracts oval, hyaline-margined. On high rocky ridges, 
N. E. Oregon and adjacent Idaho. ”’ 
* * More naked-panicnlate or thyrsoid, at least the upper heads or 
clusters exceeding the subtending leaves: heads comparatively small, 
and few-flowered, mostly oblong, 1-2 lines long; involucral bracts 
rather firm in texture, wellimbricated. the outer successively shorter. 
A. arbuscula Nutt. 1.c. Dwarf. 8-12 inches high, with astout base 
and slender flowering branches: leaves short, cuneate or fan-shaped, 
3-lobed or parted with the lobes obovate to spatulate-linear, sometimes 
again 2-lobed; those subtending the heads usually entire and narrow: 
panicle strict and comparatively simple and naked, often spiciform and re- 
duced to few rather scattered sessile heads: involucre 5-9-flowered. High 
mountains and plains, Idaho and Wyoming to Utah and California. 
A. tridentata Nutt. ].c. A shrub or small tree 2-15 feet high, much 
branched: leaves cuneate, 6-18 lines long, 3-7-toothed or lobed at the trun- 
cate summit. uppermost cuneate-linear: heads very numerons, in large 
dense panicles ; involucre 5-8 flowered, oblong, its outer or accessory bracts 
short, ovate, obtuse, tomentose-canescent. Common on dry plains and 
. 
Mountains. Commonly called Sage Brush. 
Var. angustifolia Gray Proc. Am. Acad. xix, 50. ‘ Leaves all narrow; 
lower spatulate-linear, barely 3-toothed at the roundish summit; upper 
entire and more linear, a line or less wide: heads small: shrub 8 or 4 feet 
high, with foliage too like that of the following species, but involucre of A. 
tridentata. A id plains,S. Idaho and W. New Mexico to the Mohave Des- 
ert and the southern borders of San Diego Co. California. ” 
A. trifida Nutt. l.c. Silky-canescent: Stems 6-30 inches h’gh, much 
branched: leaves 3-cleft toward the apex or 3-parted, the lobes and en! ire 
upper leaves narrowly linear or slightly spatulate dilated: head: numerous 
in the contracted leafy panicle, or spicately disposed on its branches: invo- 
lucre 3-9-flowered, its outer or accessory bracts oblong to short-linear or 
lanceolate. Elevated plains, Washington to California. 
Tribe vii, SENECIONIDE Gray Syn. Fl. i, pt. 2.79. Heads 
heterogamous or homogamous. Involucre mostly one or two series of 
equal not scarious bracts. sometimes wnequal, or even imbricated, 
with or without short accessory ones at base. Receptacle naked. 
Anthers without tails at base, but not rarely srgittate. Style-bran- 
ches of hermaphrodite flowers most commonly truncate or obtuse, 
tipped with short appendages or none. Pappus of numerous capil- 
lary bristles, sometimes caducous. 
mountains, Brit. Columbia to California and Nebraska, east of the Cascade 
* Heads sul dicecious: style in the tubular sterile flowers undivided 
or neatly so. : 
