2. Packera antennariifolia (Britton) W. A. Weber & Á. Löve, Phytologia. 49: 45. 1981.
Senecio antennariifolius Britton in N. L. Britton and A. Brown, Ill. Fl. N. U.S. 3: 478,fig. 4040. 1898
Perennials, 20–40+ cm; rhizomatous (rhizomes branched, horizontal to suberect). Stems 1 (sometimes from rosettes, rosettes sometimes clustered), tomentose. Basal leaves petiolate; blades broadly lanceolate to elliptic or spatulate, 20–40+ × 10–20+ mm, bases tapering, margins entire or subentire to dentate distally (faces tomentose). Cauline leaves abruptly reduced (petiolate or sessile; narrowly lanceolate to sublyrate, sharply toothed to pinnatisect or entire). Heads 6–12+ in corymbiform arrays (lateral cymiform arrays sometimes originating in leaf axils). Peduncles bracteate, densely lanate to sparsely tomentose. Calyculi inconspicuous. Phyllaries 13 or 21, green, 5–7 mm, densely tomentose (apices scarious). Ray florets 8–10(–13); corolla laminae 5–10 mm. Disc florets 25–35+; corolla tubes 3–4 mm, limbs 1.5–2 mm. Cypselae 1–1.5 mm, hirtellous on ribs; pappi 4–5 mm. 2n = 46.
Flowering late Apr–late May. Slopes on shale barrens; 300–800 m; Md., Pa., Va., W.Va.
Packera antennariifolia is known only from shale barrens or shale-derived soils in central Appalachia. Plants growing on steep slopes have stouter, more horizontal caudices and more extensive fibrous roots than specimens from other locations. Specimens from shale-derived soils, not growing directly on shale barrens, have weakly lobulate leaves and noticeably less hairiness.