Mohr's Rosinweed

Plants caulescent, 40–160 cm; fibrous rooted. Stems terete, shaggy-hispid. Leaves: basal persistent, petiolate; cauline usually alternate, sometimes opposite, petiolate or sessile; blades lanceolate to narrowly ovate, 1.5–26 × 0.5–14 cm, bases attenuate to acute, margins coarsely toothed or entire, apices acuminate, faces shaggy-hispid. Phyllaries 14–19 in 2–3 series, outer appressed, apices acuminate to acute, abaxial faces shaggy-hispid. Ray florets 10–20; corollas pale yellow. Disc florets 40–85; corollas pale yellow. Cypselae 6–10 × 4–7 mm; pappi 1–2 mm.

Silphium mohrii, known by the common names Mohr's rosinweed and shaggy rosinweed, is a species of flowering plant in the family Asteraceae. It is native to the Southeastern United States, where it is native only to northern Alabama, southern Tennessee, and extreme northwest Georgia. It is native to prairie remnants and rocky limestone openings. Because of its restricted range and severely declined habitat, it is considered a vulnerable species.

It produces heads of yellow flowers in late summer.