[The Genus Arnica East of the Cascade Mountains of Oregon and Washington]

Chamisso Arnica, Leafy Arnica, Narrowleaf Arnica

Arnica chamissonis ssp. foliosa

Synonyms: Arnica chamissonis ssp. foliosa var. andina, Arnica chamissonis var. andina, Arnica chamissonis var. foliosa, Arnica chamissonis var. jepsoniana, Arnica foliosa

Involucral bracts of Chamisso Arnica, Leafy Arnica, Narrowleaf Arnica: Arnica chamissonis ssp. foliosa (Synonyms: Arnica chamissonis ssp. foliosa var. andina, Arnica chamissonis var. andina, Arnica chamissonis var. foliosa, Arnica chamissonis var. jepsoniana, Arnica foliosa)

Note the tufts of hair at the tips of the involucral bracts which help identify this species.

Characteristics:

Chamisso arnica is a perenial wildflower with single stems arising 20-100 cm high from long, nearly naked rhizomes. The herbage of both the stems and leaves varires from spreading hairy to covered with matted to tangled, soft, woolly hairs. The 5-10 pairs of leaves are typically found on the stems. Those leaves of the lower to mid stem are the largest, but the upper leaves remain fairly large rather than being greatly reduced. The lower leaves are petiolate, while those of mid- and upper stem are sessile. Individual leaves are lancolate to oblanceolate, or perhaps even narrowly elliptical. The blades measure 5-3- cm long and are 1-4 cm wide. The leaf margins vary from lightly toothed to entire.

The open inflorescence consists of several to up to a dozen loosely spaced flower heads, each of which is bell-shaped at the base. The involucral bracts are 8-13 mm long and obtuse to somewhat acute at the tip, bearing a tuft of long white hairs at the tip. The approximately 13 rays are pale yellow, each measuring 1.5-2 cm long. These surround a yellow cluster of disk flowers which measure 7-11 mm long.


Habitat:

Chamisson arnica may be found from the foothills to middle and subalpine elevations in the mountains. It is a plant of vernally wet meadows and wet places, or moist woodland edges.


Range:

Chamisso arnica may be found from Alaska south to California and east to the Yukon and Hudson's Bay and hence south to central Nevada, southern Utah and Eastern Arizona.


Flower head of Chamisso Arnica, Leafy Arnica, Narrowleaf Arnica: Arnica chamissonis ssp. foliosa (Synonyms: Arnica chamissonis ssp. foliosa var. andina, Arnica chamissonis var. andina, Arnica chamissonis var. foliosa, Arnica chamissonis var. jepsoniana, Arnica foliosa) - Involucral bracts of Chamisso Arnica, Leafy Arnica, Narrowleaf Arnica: Arnica chamissonis ssp. foliosa (Synonyms: Arnica chamissonis ssp. foliosa var. andina, Arnica chamissonis var. andina, Arnica chamissonis var. foliosa, Arnica chamissonis var. jepsoniana, Arnica foliosa)

Close-ups of the flower head and involucral bracts of Chamisso arnica. Note the tufts of hairs at the tips of the involucral bracts (a diagnostic characteristic of this arnica species).

Chamisso Arnica, Leafy Arnica, Narrowleaf Arnica: Arnica chamissonis ssp. foliosa (Synonyms: Arnica chamissonis ssp. foliosa var. andina, Arnica chamissonis var. andina, Arnica chamissonis var. foliosa, Arnica chamissonis var. jepsoniana, Arnica foliosa) - Close-up of the inflorescence of Chamisso Arnica, Leafy Arnica, Narrowleaf Arnica: Arnica chamissonis ssp. foliosa (Synonyms: Arnica chamissonis ssp. foliosa var. andina, Arnica chamissonis var. andina, Arnica chamissonis var. foliosa, Arnica chamissonis var. jepsoniana, Arnica foliosa)

Chamisso arnica as seen near the high water mark of a moist meadow that is a remnant of an old reservoir about one mile above Olive Lake, Umatilla National Forest.........July 18, 2013.

Leaf and stem of Chamisso Arnica, Leafy Arnica, Narrowleaf Arnica: Arnica chamissonis ssp. foliosa (Synonyms: Arnica chamissonis ssp. foliosa var. andina, Arnica chamissonis var. andina, Arnica chamissonis var. foliosa, Arnica chamissonis var. jepsoniana, Arnica foliosa)

The hair stem and leaf base of Chamisso arnica. Note the variation in hair type on the stem and leaves.

Chamisso Arnica, Leafy Arnica, Narrowleaf Arnica: Arnica chamissonis ssp. foliosa (Synonyms: Arnica chamissonis ssp. foliosa var. andina, Arnica chamissonis var. andina, Arnica chamissonis var. foliosa, Arnica chamissonis var. jepsoniana, Arnica foliosa)

Chamisso arnica as seen at a small tarn on the south side of the north loop road about one mile above Fish Lake on the Steens Mt., southeastern Oregon...................July 28, 2004. Note that this species generally has 5 or more pairs of stem leaves (one of its diagnostic characteristics!).

Paul Slichter