Arnica ovata (previously arnica diversifolia) is a sparsely-leaved plant; stems usually have just two or three pairs, the largest about half way up. Those lower down have stalks; the uppermost pair is stalkless. Leaves, stems and involucres are all covered with short, sticky, glandular hairs.
Plants have a small number of flowerheads, usually one, two or three, each with between 8 and 13 wide, grooved ray florets and a center of small disc florets (fewer than in many similar species) that elongate as they mature. The flower head is supported by a ring of green, pointed involucral bracts. The plant is less common than some other arnicas, restricted to medium to high elevation areas in the mountains of the Pacific and northern Rocky Mountain states.