1. Heads with conspicuous rays clearly exceeding the involucre.
1. Heads with rays minute or none.
2. Leaves and stems densely glandular pubescent; bracteoles at base of involucre (2–) 2.5–5.5 mm long.
2. Leaves and stems glabrate to densely pubescent, but glandular hairs absent or sparse; bracteoles at base of involucre 0.9–2.6 mm long.
3. Bracteoles at base of involucre and involural bracts with greenish tips (unicolorous); rays present but minute; plant densely pubescent, with glandular hairs sometimes present but sparse.
3. Bracteoles and involucral bracts greenish with conspicuous blackish tips; rays none; plant without glandular-viscid hairs (glabrate to somewhat tomentose).
All species found in Senecio
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 17, 2017. http://www.michiganflora.net/genus.aspx?id=Senecio.