Arnica parryi (Parryi's Arnica)
Asteraceae (Sunflower Family)

Montane, subalpine. Woodland openings, meadows. Summer.
Shoulder of Lone Cone, August 8, 2011.

Arnica parryi (Parry's Arnica)
Asteraceae (Sunflower Family)

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

This Arnica is almost always rayless and nodding in bud, as you can see in the above photographs. Arnica parryi generally grows at medium-to-high montane elevations, 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. 

Arnica parryi grows to a very slim 20 inches tall, has erect or nodding flower heads, clustered basal leaves, up to four pairs of shorter stem leaves, and phyllaries often edged in purple.  In the next photograph at left you can see the hairy, green phyllaries which form a green, cup-shaped enclosure below the golden flower head.

Arnica parryi was first collected in Clear Creek, Colorado in 1861 by eminent Colorado botanist, Charles Parry, and it was named for Parry in 1874 by Asa Gray.  (Click for more biographical information about Parry.) 

The word "Arnica" is considered by most botanical etymologists to be of unknown origin, but "arn" is Greek for "lamb" so perhaps the meaning is, "like lamb's skin," referring to the downy soft leaves.

Arnica parryi (Parry's Arnica)
Asteraceae (Sunflower Family)

Montane, subalpine. Woodland openings, meadows. Summer.
Upper Calico Trail, July 21, 2005 and
U.S. Basin, August 9, 2017.

Flower heads of Arnica mollis consist of dozens of tightly packed tubular flowers, botanically called "disk flowers". The disk flowers, as you can see in the photograph at top left, have triangular lobes (see especially the disk flower at the 2 o'clock position) and these lobes can sometimes appear to be short ray flowers fooling you into thinking that you are looking at an Arnica with ray flowers, probably Arnica mollis. Complicating identifications a bit is the fact that on rare occasions A. parryi does have ray flowers. Also, when the two species are in bud, Arnica parryi and Arnica mollis can be very difficult to distinguish from each other.

Several characteristics will help you separate the two species:

1) If you are in the alpine and looking at hundreds of plants, they are surely Arnica mollis, not Arnica parryi.
2) Although the photograph at top left of this page shows several dozen A. parryi plants tightly grouped, that posture is far more common for A. mollis. A. parryi plants are most often well-spaced from one another.
3) Arnica parryi individual plants have 3-12 flower heads; A. mollis plants have 1-5.
4) The seeds of A. parryi are usually glabrous; A. mollis has hairy seeds.
5) A. parryi has a bell-shaped involucre; A. mollis has a more hemispheric-shaped involucre.
6) The involucral bracts of A. parryi are narrowly lanceolate; those of A. mollis are more broadly lanceolate to elliptic.
7) Tips of A. parryi involucral bracts are most often green and acute; those of A. mollis are tinged with red and acuminate.

Arnica parryi (Parry's Arnica)
Asteraceae (Sunflower Family)

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

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

Arnica rydbergii (Rydberg's Arnica)
Asteraceae (Sunflower Family)

Subalpine, alpine. Rocks. Summer.
Stony Pass, July 17, 2010.

Found isolated or in scattered patches, this bright yellow Arnica prefers subalpine and alpine rocky areas. Few pairs of widely spaced stem leaves can be slightly serrated.  Basal leaves are clustered and usually have petioles. As the photograph indicates, 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. Rydberg wrote Flora of the Rocky Mountains and Adjacent Plains in 1917. (Click for more biographical information about Rydberg.)

Arnica rydbergii (Rydberg's Arnica)
Asteraceae (Sunflower Family)

Subalpine, alpine. Rocks. Summer.
Stony Pass, July 17, 2010.

Phyllaries of this species of Arnica are narrow, pointed, often red (anthocyanic) at the tip, lightly hairy, and in one row.  Ray flowers usually number 7-12.

The second photograph shows the bright white pappus hairs that are attached to the top of the white seed. Both the ray flowers and the disk flowers have these hairs, which, in the case of A. rydbergii, are barbed all along their length. The barbs can be seen with a 10x hand lens  --  a tool which opens up a huge world of wonder not visible to our unassisted eyes.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Arnica parryi

Range map for Arnica rydbergia