Plants 8-12(-20) dm. Stems scab-rellous to pilosulous, glabrescent. Leaves mostly cauline; blades lance-linear, 6-14(-20) cm × 7-15(-25) mm, l/w = 7-10(-18), abaxially scabrellous (hairs awl-shaped), resin-gland-dotted, adaxially scaberulous, glabrescent, resin-gland-dotted. Heads in ± corymbiform arrays. Peduncles 2-5 cm. Involucres ± hemispheric, 11-15 × 11-15 mm. Phyllaries (50-)60-70+ in 5-6 series, scabrellous (and resin-gland-dotted), margins ciliolate, the outer lance-ovate, 3-8+ mm, inner lanceolate, 12-15 mm, tips subulate to filiform. Florets 50-100+. Cypselae 3-5 mm; pappi fuscous to purplish, outer scales 25-30+, 0.5-1 mm, contrasting with 25-30+, 5-7 mm inner bristles. 2n = 34. Flowering Aug-Oct. Leas, roadsides, stream banks, in sand or on limestone; 200-300 m; Ark., Kans., Mo., Okla. Vernonia arkansana was published in April, V. crinita in October 1838.
Stems 0.7-1.5(-2) m, glabrous or nearly so (or more puberulent above) and somewhat glaucous; lvs linear or lance-linear, 10-20 נ0.5-2.5 cm, acuminate, denticulate or sometimes entire, glabrous or rarely thinly hairy, pitted-punctate beneath; infl very irregular, the pedicels 1-5 cm, thickened at the top; fls mostly 55-100+; invol 9-15 mm, its bracts arachnoid-ciliate, linear or narrowly lanceolate at the appressed base, with loosely flexuous filiform tip 2-4 mm; pappus brownish-purple; 2n=34. Low woods and streambanks; Ozark region of Mo., s. Ill., Ark., Okla., and Kans., occasionally intr. n. and e. to Wis. (V. crinita)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.