[The Genus Arnica East of the Cascade Mts.]

Leafy Arnica, Meadow Arnica, Chamisso Arnica

Arnica chamissonis

A close-up of the involucral bracts of Chamisso arnica found along Kreps Lane in Conboy National Wildlife Refuge...........July 2, 2006. Note the rounded to slightly acute tips to the bracts, tipped with tufts of whitish hairs, both of which are diagnostic features of this species.

Characteristics:

Chamisso arnica is a perennial wildflower with single stems arising 20-100 cm high from long, nearly naked rhizomes. The herbage of both the stems and leaves varies from spreading hairy to covered with matted to tangled, soft, wooly 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 lanceolate to oblanceolate, or perhaps even narrowly elliptical. The blades measure 5-30 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:

Chamisso arnica may be found from the foothills to middle and subalpine elevations in the mountains. It is a plant of meadows and wet places, or most 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.


The photo above shows a close-up of the flower head of Chamisso arnica as found along Kreps Lane in Conboy National Wildlife Refuge...........July 2, 2006.

The photo above shows another view of the involucral bracts with the distinct tufts of hairs at the tips of each bract as seen along Kreps Lane in Conboy National Wildlife Refuge...........July 2, 2006.

The photo above shows one of the paired stem leaves of Chamisso arnica as found along Kreps Lane in Conboy National Wildlife Refuge...........July 2, 2006. This species typically has more than 5 pairs of stem leaves per stem.

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

The photo above shows 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