Pine barren thoroughwort

Perennials, 40–100+ cm. Stems (from short rhizomes) single, branched distally (among heads), puberulent throughout. Leaves usually opposite (distal sometimes alternate); sessile; blades pinnately nerved, narrowly elliptic, 40–100+ × 5–20 mm, bases cuneate (not perfoliate), margins serrate, apices acute to acuminate, faces puberulent, gland-dotted. Heads in corymbiform arrays. Phyllaries 10–12 in 2–3 series, elliptic to oblong, 1.5–4 × 0.8–1 mm, apices broadly acute to acute, abaxial faces puberulent, gland-dotted. Florets 9–14; corollas 3–3.5 mm. Cypselae 2–3 mm; pappi of 20–30 bristles 3–3.5 mm. 2n = 20.

Flowering Aug–Sep. Moist, low ground, pocosins, bogs, cutover woodlands, pine barrens, acid soils; 20–100+ m; N.J., N.C., S.C.

Eupatorium resinosum is in the Center for Plant Conservation’s National Collection of Endangered Plants.