Asteraceae : Arnica cordifolia

Arnica cordifolia is a perennial herb arising from long, creeping rhizomes, growing to 60 cm tall. It has two to four sets of opposite leaves on the flowering stem, each having a long petiole. Basal leaves are cordate, with long petioles and dentate margins. The cauline leaves are heart-shaped to arrowhead-shaped, with finely dentate margins. Leaf blades are 4-12 cm long and 2-9 cm wide. The inflorescence is composed of a single or occasionally 2-3 turbinate to campanulate heads, each 5–9 cm wide. The involucral bracts are 1-2 cm long, covered with white-hairs and sometimes studded with resin glands. Each head has 10-15 ray flowers with ligules 15-30 mm long and the center of each head contains several golden yellow disc florets. The achenes are 6-9 mm long with short hairs and/or glands. The pappus has long white barbed hairs. The flowers usually bloom from May through August. Heartleaf arnica grows in western South Dakota.