Tall Ironweed

Plants 5–10+ dm. Stems sparsely appressed-puberulent, glabrescent. Leaves mostly cauline; blades (mid stem) lance-linear to filiform, 5–12 cm × 2–4(–8+) mm, l/w = (8–)12–30(–60+), abaxially glabrous but for scattered hairs on midribs or scabrellous (hairs awl-shaped), resin-gland-dotted or not, adaxially scabrellous. Heads in ± corymbiform to paniculiform arrays. Peduncles 8–25 mm. Involucres ± campanulate to obconic, 5–7(–10) × 4–6(–9) mm. Phyllaries 22–45+ in 5–6 series, sparsely scabrellous, glabrescent, margins ciliolate, the outer lanceolate to subulate, 1.5–3 mm, inner lance-ovate to lanceolate, 5–9+ mm, tips acuminate to subulate. Florets 12–20(–30). Cypselae 2.5–3 mm; pappi stramineous to purplish, outer scales 25–30, 0.5–1.2+ mm, contrasting with 35–40+, 5.5–6+ mm inner bristles. 2n = 34.

Vernonia angustifolia subsp. mohrii (S. B. Jones) S. B. Jones & W. Z. Faust; V. angustifolia subsp. scaberrima (Nuttall) S. B. Jones & W. Z. Faust; V. angustifolia var. scaberrima (Nuttall) A. Gray; V. scaberrima Nuttall