Rydberg's Arnica Arnica rydbergii Aster family (Asteraceae)
Found isolated or in scattered patches, this bright yellow Arnica prefers and rocky areas. Few pairs of widely spaced stem leaves can be slightly . are clustered and usually have . Stems can start off at an angle and then gradually turn vertical. The species name was given in 1899 by Edward Greene to honor Per Axel Rydberg, a giant in Colorado botany, and a major influence on Bill Weber, the present-day Colorado plant authority. Rydberg wrote a "Flora of the Rocky Mountains and Adjacent Plains" in 1917.
Low-growing with foliage. Flowering stems usually bear a solitary flower head. Occasionally 2-3 flower heads are produced per plant. Flowering stems are often separate from clusters of . Leaves are to in outline, about 2" long and may be toothless or slightly along the margins. Three to four leaf pairs are produced each other along the erect stems, but only the have . Flowers are produced in densely clustered, broadly conical flower heads at the top of stems. A central button of dark yellow flowers is surrounded by 7-10 yellow , each about 0.75 long. is densely short-hairy .
