provided by North American Flora
Sphaeromeria argentea Nutt. Trans. Am. Phil. Soc. II. 7: 402
Tanacelum Nullallii 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, corymbose; involucre rounded-campanulate tonearly hemispheric, 3.5 mm. high, 5-6 mm. broad; bracts about 1 2, 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. Distribution: Arid hills, Wyoming and Montana.
- bibliographic citation
- Per Axel Rydberg. 1916. (CARDUALES); CARDUACEAE; TAGETEAE, ANTHEMIDEAE. North American flora. vol 34(3). New York Botanical Garden, New York, NY