[The Genus Arnica East of the Cascade Mts. of Oregon and Washington]
Longleaf Arnica, Seep Spring Arnica, Spearleaf Arnica, Spear-leaf Arnica, Spear-leaf Leopardbane
Arnica longifolia
Synonyms: Arnica longifolia ssp. myriadenia, Arnica myriadenia
A nice speciman of longleaf arnica found along
the South Loop Road at a point where snow lies late into the summer about one mile downhill from the East Rim Viewpoint, Steens Mountain, Harney County, Oregon...........August 31,
2011.
The photo at right shows longleaf
arnica as found along the Wildhorse Trail at the Steens Mt., southeastern Oregon...........July
16, 2002.
Characteristics:
Longleaf arnica is an attractive perennial wildflower often found in large
clumps which are the result of a much branched system of rhizomes. The numerous
stems contain mostly 5-7 opposite pairs of leaves and range from 30-60 cm high.
The lower leaves often begin whithering by bloom tim, and the mid and upper
leaves are often quite large, measuting from 5-12 cm long and from 1-2 cm wide.
Individual leaves are narrowly lanceolate or lance-elliptic in shape, tapering
gradually to an acute tip. The margins are mostly entire or occasionally slightly
toothed. The herbage is somewhat rough and occasionally sticky.
The flower heads are several to many, with the involucres from 7-10 mm high.
The 13-21 bracts are lanceolate in shape and densely glandular hairy with pointed
tips. The 8-13 rays are yellowish and 1-2 cm long, surrounding the central disk
(See photo above.).
Habitat:
Longleaf arnica may be found about seeps and springs as well as on moist cliffs
and streambanks at middle and upper elevations in the mountains. Its elevation
range is 2100-3250 meters.
Range:
Longleaf arnica may be found from the Washington Cascades south to the Sweetwater
and White Mts. of California and east to Montana, southwestern Alberta, and
Colorado and central and southwestern Utah.
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Longleaf arnica as seen (left) along the North Loop Road about one-half mile east of the Kiger Gorge Overlook, Steens Mountain, Harney County, Oregon...............August 31, 2011. The photo at right shows longleaf arnica as seen in a steep drainage along the East Fork Lostine River #1662 uphill to the west of Lost Lake, Eagle Cap Wilderness..........August 4, 2016.
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Longleaf arnica found on talus slopes near the trailhead for the Roads End Trail, Strawberry Mountain Wilderness..........August 19,
2011.
Longleaf arnica blooming along Lick Creek Trail #231 at a crossing of Lick Creek, Hells Canyon National Recreation Area.......August 11, 2018.
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Longleaf arnica found along the Wildhorse Trail at the Steens
Mt., southeastern Oregon.........July 16, 2002. Note the numerous pairs of
stem leaves.
Paul Slichter