ParT 3, 1916] CARDUACEAE: ANTHEMIDEAE 241 
1. Sphaeromeria simplex (A. Nelson) A. Heller, Muhlenbergia 
lee 7/s  “Alexaloe 
Tanacetum simplex A. Nelson, Bull. Torrey Club 26: 484. 1899. 
A tufted perennial, with a short cespitose woody caudex; stems about 1 dm. high, silky- 
canescent; leaves crowded at the base, closely and finely silky-canescent, simple and linear, 
2-4 em. long, 1-2 mm. wide, or bifid or trifid at the apex; stem-leaves few and linear, entire; 
heads solitary at the end of the stems; involucre 5-6 mm. high, 8-10 mm. broad; bracts about 
25, in two series, light-yellow with green midrib, shining, silky, oval or obovate, or the outer 
ovate-lanceolate; ray-flowers few; corollas 3—4-lobed, lance-ovoid, 3 mm. long; disk-corollas 
campanulate with a short tube, glabrous, 3-3.5 mm. long; achenes about 2 mm. long, truncate 
at the apex. 
TYPE LocaLity: Near Laramie, Wyoming. 
DISTRIBUTION: Wyoming. 
2. Sphaeromeria capitata Nutt. Trans. Am. Phil. Soc. II. 7: 402. 
1841. 
Tanacetum capitatum T. & G. Fl. N. Am. 2: 415. 1843. 
A cespitose tufted perennial, suffruticose at the base; stems about 1 dm. high, finely 
canescent; leaves mostly crowded at the base, 1-3 em. long, silvery-canescent, ternately or 
biternately divided into linear or linear-oblanceolate divisions; heads few, capitately clustered 
at the end of the stems or sometimes 1 or 2 in the upper axils below the terminal cluster; 
involucre broadly campanulate, 4-5 mm. high and about as broad; bracts 6-8, obovate, light- 
yellow, erose, silky; ray-flowers 5—6; corollas 2 mm. long, ovoid, 3—4-lobed; disk-flowers 12-15; 
corollas campanulate, with a short tube, 2.5 mm. long, glandular-puberulent; achenes 2 mm. 
long, subcylindric, tapering at the base, 5-ribbed, truncate at the summit, glabrous. 
TyPE LocaLity: Red Buttes on the Platte, Wyoming. 
DISTRIBUTION: Wyoming and southern Montana. 
3. Sphaeromeria argentea Nutt. Trans. Am. Phil. Soc. II. 7: 402. 
1841. 
Tanacetum Nuttallii T. & G. Fl. N. Am. 2: 415. 1843. 
A suffruticose perennial; stems cespitose and decumbent at the base, 1-2 dm. high; leaves 
broadly cuneate, obtusely 3-5-lobed at the summit, densely silvery-white; heads few, corym- 
bose; involucre rounded-campanulate tonearly hemispheric, 3.5 mm. high, 5-6 mm. broad; 
bracts about 12, light yellowish-brown with darker midrib, scarious and erose on the margins, 
the outer ovate and acute, the inner oval and obtuse; ray-corollas ovoid, 1.5 mm. long, 4-lobed, 
glandular-puberulent; disk-flowers many; corollas campanulate, with a short tube, 2 mm. 
long, glandular-puberulent; achenes 2 mm. long, subcylindric, truncate at the apex, 10-ribbed. 
Type LocaLity: Near the sources of the Platte, Wyoming. 
Distripution: Arid hills, Wyoming and Montana. 
4, Sphaeromeria cana (D. C. Eaton) A. Heller, Muhlenbergia 
1? 7: 1900: 
Tanacetum canum D. C. Eaton, in S. Wats. Bot. King’s Expl. 179, 1871. 
A low shrub, 2-6 dm. high; branches silky-canescent when young; leaves silvery-canescent, 
1-5 em. long, the lower pedately 3-5-fid into oblanceolate divisions, the upper lanceolate or 
oblanceolate, undivided; heads several, corymbose; involucre hemispheric, 3 mm. high, 
5-6 mm. broad; bracts 10-12, canescent, yellowish, elliptic to obovate, obtuse; ray-flowers 
4-8; corollas nearly 2 mm. long, cylindric, obscurely 3—4-lobed; lobes short-villous; disk-flowers 
50-60; corollas campanulate, with a short tube, 2 mm. long, with short-villous lobes; achenes 
1.5 mm. long, cylindric, 10-ribbed, truncate at the apex. 
Tyre LocaLity: East Humboldt Mountains, Nevada. 
Disreimution: Nevada, eastern California, and Oregon. 
ILLustTRation: S. Wats. Bot. King’s Expl. pl. 19, f. 8-14. 
