Heartleaf Arnica

Plants 10–40(–70) cm. Stems usu-ally simple, sometimes branched. Leaves 2–4(–6) pairs, mostly cauline (basal often persistent on sterile rosettes); petiolate; blades cordate or subcordate to ovate, 3–10 × 2–10 cm, margins dentate to coarsely dentate, apices acute to rounded, faces puberulent to sparsely villous, sometimes stipitate-glandular (especially adaxial). Heads 1, or 3–5(–10). Involucres broadly campanulate. Phyllaries 10–20, narrowly ovate to lanceolate. Ray florets 6–13; corollas yellow. Disc florets: corollas yellow; anthers yellow. Cypselae dark gray, 5–10 mm, sparsely to densely hirsute (hairs duplex), sometimes stipitate-glandular as well; pappi white, bristles barbellate. 2n = 38, 57, 76, 95, 114.

Arnica cordifolia var. pumila (Rydberg) Maguire; A. paniculata A. Nelson; A. whitneyi Fernald