Arnica cordifolia (Heartleaf Arnica)
Asteraceae (Sunflower Family)

Montane, subalpine. Woodlands. Summer.
Lizard Head Trail, June 19, 2004.

This is a most common and bright mountain flower and the most common of all Arnicas in our area.  It thrives in the dry, acid soils under Spruce and as one enters the dark forest shade from sunny meadows, the bright lemon-yellow Arnica flowers are like beams of lights.  It is common to see dozens of flowering Arnica plants in one patch with hundreds of leafy, flowerless plants carpeting the ground around them (see photo below).

Since seeds of Arnica cordifolia are produced without fertilization, off-spring are genetically identical to their parents.  The patches of Arnica cordifolia are, therefore, clones and this accounts for the wide variability of Arnica cordifolia characteristics from one location to another: since there is no pollination there is no blending of characteristics to a common denominator.

"Cordifolia" means "heart-leaf", but Arnica cordifolia leaf shape is highly variable (the top leaves in the photo are elongated, the bottom heart-shaped).  The word "Arnica" means "lamb's skin," and probably refers to the downy soft leaves.

Thomas Drummond collected the first specimen of Arnica cordifolia (as well as Arnica mollis shown below) in the Canadian Rockies in the 1820s and it was named by William Hooker in his Flora Boreali-American in 1834.

Arnica cordifolia (Heartleaf Arnica)
Asteraceae (Sunflower Family)

Montane, subalpine. Woodlands. Summer.
Colorado Trail, July 15, 2005.

Arnica cordifolia (Heartleaf Arnica)
Asteraceae (Sunflower Family)

Montane, subalpine. Woodlands. Summer.
Sneffels Highline Trail, August 4, 2004.

Arnica parryi (Arnica)
Asteraceae (Sunflower Family)

Montane, subalpine. Woodland openings, meadows. Summer.
Upper Calico Trail, July 21, 2005.

This rayless Arnica generally grows at the same altitudes as the other Arnicas pictured on this web site, but it rarely reaches the alpine zone.  It does not usually grow as densely as Arnica cordifolia and Arnica mollis but it does grow in patches of many dozens of plants -- as well as in small scattered patches.  It grows to a very slim 20 inches tall, has nodding flower buds, erect flowers, clustered basal leaves, up to four pairs of shorter stem leaves, and phyllaries edged in purple.  (The phyllaries are the hairy, green, cup-shaped enclosure below the golden flower.)

Fall leaf color is a very subtle light gray-maroon.

This species was first collected by Charles Parry, eminent 19th century Colorado botanist, in Clear Creek, Colorado in the early 1860s and was named for Parry in 1864 by Asa Gray.  (More biographical information.)

Arnica rydbergii (Arnica)
Asteraceae (Sunflower Family)

Subalpine, alpine. Rocks. Summer.
Lizard Head Trail, August 31, 2004.

Found isolated or in scattered patches, this bright yellow Arnica prefers subalpine and alpine rocky areas. Widely spaced leaves can be slightly serrated.

The species name was given in 1899 by Edward Greene to honor Per Axel Rydberg, a giant in Colorado botany. He wrote Flora of the Rocky Mountains and Adjacent Plains in 1917. (More biographical information.)

Arnica rydbergii (Arnica)
Asteraceae (Sunflower Family)

Subalpine, alpine. Rocks. Summer.
Lizard Head Trail, August 31, 2004.