There are a good many kinds of Arnica, natives of the northern hemisphere. This is the ancient name and a European kind is much used medicinally.
Heart-leaved Arnica
Árnica cordifòlia
Yellow
Summer
West, except Ariz.
A handsome mountain flower, with a hairy stem, from six inches to two feet tall, and velvety leaves, coarsely toothed, the lower ones usually heart-shaped. The flower-heads are usually single, over two inches across, with bright yellow rays, an orange center, and a hairy involucre. This is common in rich moist soil in mountain valleys, as far east as Colorado.
Broad-leaved Arnica
Árnica latifòlia
Yellow
Summer
Northwest
A handsome kind, sometimes a foot and a half tall, with pretty flowers, about two inches across, with very bright yellow rays. The bright green leaves are thin in texture and practically smooth, the lower ones more or less roundish, with leaf stalks. This grows in mountain woods.
There are many kinds of Artemisia; herbs or shrubs, usually bitter and aromatic, widely distributed.
Common Sage-brush
Artemísia tridentàta
Yellow
Summer, autumn
West, etc.
This is the characteristic sort, often immensely abundant and found as far east as Colorado, often tinting the landscape for miles with its pale and beautiful foliage and one of the dominant shrubs in the Great Basin. It is very branching, from one to twelve feet high, with a distinct trunk and shreddy bark, and the twigs and alternate leaves are all gray-green, covered with silvery down, the upper leaves small and toothless, the lower wedge-shaped, with usually three, blunt teeth. The small yellow flowers have no rays and grow in small, close clusters, forming long sprays towards the ends of the branches. Sagebrush is a "soil indicator" and when the prospective rancher finds it on land he knows at once that it will be good for even dry farming, as the soil contains no salt or alkali.
Xylorrhiza tortifolia.