Vernonia baldwinii Torr.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Stems 6–15 dm, thinly pubescent to commonly tomentose; lvs lance-ovate to ovate, 7–17 × 2–6 cm, acute or shortly acuminate, sharply serrate, puberulent above, tomentose beneath, with long, crooked hairs; infl 1–2 dm wide, flattened or irregular; heads mostly very numerous; fls 17–34; invol 5–8 mm, its principal bracts lanceolate or lance-ovate, acuminate, arachnoid- ciliate, densely resinous toward the tip on both sides of the prominent (often keeled) midvein; pappus rather light brown or brownish-purple; 2n=34. Dry prairies, plains, and upland woods. The Ozarkian var. baldwinii, occurring from w. Ill. to Mo., Ark., and e. Okla., has mostly 23–34 fls; the tips of the invol bracts are recurved, those of the inner pubescent on the inner surface. The var. interior (Small) Schubert, mainly on the Great Plains from s. Io. and Nebr. to e. Colo. and s. Tex., often weedy, has mostly 17–27 fls; the tips of the invol bracts are merely loosely spreading, not pubescent within. (V. interior)