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Key to Heterotheca

Asteraceae

Heterotheca

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1 Leaf margins entire; leaves appearing green or gray; leaves 3-15× as long as wide; [MO, OK, and TX westwards].
  2 Leaves appearing gray, with a dense pubescence of appressed or curving hairs which mostly lacking a pustular base; leaf blades of leaves on flowering branches mostly 3-5× as long as wide
  2 Leaves appearing green, with a sparse pubescence of spreading, bristly hairs which mostly have a pustular base (best seen at 10× magnification); leaf blades of leaves on flowering branches mostly 8-15× as long as wide
1 Leaf margins (at least of some of the leaves) toothed; leaves appearing green or very slightly grayish, scabrous, also pubescent with spreading to curved hairs, the longer hairs at least with a pustular base; leaves 2-5× as long as wide; [collectively widespread in our area].
    3 Ray flowers without pappus; annual or biennial, taprooted; upper leaves rounded to clasping at the sessile base, lower leaves (deciduous by late in the season) petiolate; fruits developing from the ray florets 3- or 4-angled, glabrous or slightly strigose
    3 Ray flowers with pappus; perennial, from creeping rhizomes; upper and lower leaves cuneate to a sessile base; fruits developing from the ray florets 2-angled (flattened), moderately to densely hairy.
      4 Stems 4-8 (-10) dm tall; branches and upper stem lacking glands or sparsely to moderately glandular (in addition to the longer, nonglandular hairs)
      4 Stems (6-) 8-14 dm tall; branches and upper stem moderately to densely glandular (in addition to the longer, nonglandular hairs)