1 Involucre 2-3 mm high; plants 3-15 (-25) cm tall; inflorescence of many, small, axillary and terminal clusters overtopped by subtending leaves

1 Involucre 3-7 mm high; plants 15-100 cm tall; inflorescence terminal, elongate, clustered, or corymbiform.

  2 Leaves distinctly (but shortly) decurrent 1-10 mm and adnate-auriculate on the stem.

    3 Upper surface of the leaves coarsely glandular-hairy; heads in corymbiform arrays

    3 Upper surface of the leaves loosely tomentose, not glandular; heads in terminal glomerules

      4 Involucres 3-4 mm high; bisexual florets 5-10 (corollas red-tipped); cypselas with papilliform hairs

      4 Involucres 4-6 mm high; bisexual florets mostly 18-28 (corollas evenly yellowish, not red-tipped); cypselas glabrous

  2 Leaves sessile, not decurrent or adnate-auriculate.

        5 Stem glandular-pubescent or glandular-puberulent, the hairs at right angles to the stem, the stem surface plainly visible.

          6 Stems glandular-villous, the stipitate glands (0.1-) 0.3-1.0 mm high, prominently variable in height on any portion of the stem, with a stalk broadened toward the base and about equal the gland width; pistillate florets 83-107, bisexual florets 9-15; leaves mostly oblong-lanceolate, 2.5-7 cm long, 4-20 mm wide, 4-8 times longer than wide; plant 4-10 dm tall

          6 Stems glandular-puberulent, the stipitate glands 0.1-0.2 mm high, relatively even in height on any portion of the stem, with a filiform stalk of even width and narrower than the gland width; pistillate florets 47-78, bisexual florets (7-) 11-20; leaves linear to linear-lanceolate or linear-oblanceolate, 1.5-5.5 cm long, 1.5-10 mm wide, 6-10 times longer than wide; plant 3-7 dm tall

        5 Stem white-woolly or arachnoid with matted white hairs, the stem surface generally obscured (sometimes glandular-pubescent at the base of the stem only)

             7 Leaves subclasping, 1-3 mm wide, linear-lanceolate; [TX, southwards]

             7 Leaves not clasping, 2-10 (-15) mm wide, linear-lanceolate to elliptic or oblanceolate; [collectively widespread].

               8 Leaves weakly bicolored; involucres 4-5 mm high; cypselae weakly papillate-roughened; [OK, TX, westwards]

               8 Leaves strongly bicolored; involucres 5-7 mm high; cypselae smooth; [widely distributed]