This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Senecio pauperculus Michx. Fl. Bor. Am. 2: 120.
Perennial, often tufted; stems slender, 1 1/2'-20' high, woolly at the base and in the axils of the lower leaves, or essentially glabrous. Basal leaves slender-petioled, oblong, rarely slightly spatulate, very obtuse, narrowed at the base, mostly thick, crenate, or rarely dentate, often purplish, 1-5' long, 3"-6" wide, their petioles and sometimes their lower surfaces persistently tomentose or woolly, or glabrous throughout; lower stem leaves petioled, laciniate or pinnatifid, the upper sessile, very small; heads few or several, slender-peduncled, 6"-10" broad; involucre about 3" high; rays 8-12; achenes hispidulous or glabrous; pappus white.
In dry or rocky soil, Newfoundland to North Carolina, Ontario, British Columbia, Alabama, Tennessee and Nebraska. May-July.
S. Smallii Britton, Mem. Torr. Club 4: 132. 1893.
Similar to the preceding species but taller, growing in large clumps; stem 1 1/2°-2 1/2° high, slender, densely and persistently floccose-woolly at the base and in the lower axils, or finally glabrate. Basal leaves elongated-oblong or linear-oblong, obtuse or acute, long-petioled, crenate-dentate, 3'-6' long, 3"-12" wide, at first tomentose, at length nearly glabrous; stem leaves several, deeply pinnatifid, or the lower lyrate, the uppermost very small; heads very numerous, 4"-5" broad, about 2 1/2" high, slender-peduncled, forming large corymbs; rays 8-10; achenes hispidulous; pappus white.
In meadows and thickets, southeastern Pennsylvania to Florida and Alabama. May-June.
Senecio aureus var. compactus A. Gray, Syn. Fl. 1: Part 2, 391. 1884. Senecio compactus Rydberg, Mem. Torr. Club 5: 342. 1893.
Not T. Kirk. Senecio densus Greene, Pittonia 4: 226. 1900.
Perennial; stem usually tufted, low, rather stout, 6'-12' high, woolly at the base and in the lower axils, or glabrous. Basal leaves linear-cuneate, entire or 3-toothed at the apex, 1'-3' long, 2"-3" wide, thick, slender-petioled, the petioles commonly woolly-margined; lower stem leaves often much larger and broader, usually laciniate or pinnatifid, but sometimes similar to the basal, the uppermost very small and sessile; heads several, 8"-10" broad, short-peduncled in a compact corymb; rays 10-15; achenes hispidulous; pappus white.
On dry plains, Manitoba to Nebraska, Colorado and Texas. May-June.