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Leafy
Arnica
Arnica chamissonis Less.
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Family: Asteraceae,
Aster or Composite
Genus: Arnica
Description
General: 20-100 cm tall, hairy, becoming glandular above.
Growth habit:
Erect perennial with stems from long, almost
naked, slender rhizomes.
Stems:
single, leafy, with soft, wavy hairs.
 Leaves: opposite, lance-shaped, in 5-10 pairs on stem,
5-25 cm long and 1-4 cm wide, clasping stem, not much
reduced upwards, slightly toothed or entire, usually with 5
stronger veins. Lower leaves taper to winged stalks and
upper leaves are stalkless. Variously hairy with short,
woolly hairs, becoming glandular higher up.
 Flowerheads: yellow, 3-5 cm across, with 10-16 rays,
growing in branched clusters of 1 to several flowerheads.
The involucre is mostly 8-12 mm high, with bracts that are
blunt or soft-pointed, tipped with a tuft of white hairs.
Flowering time: Mostly June-July.
 Fruits: achenes, short-hairy and glandular to almost
hairless. Pappus of tawny to straw-colored, feathery
bristles.
Distribution
Mostly in meadows, thickets and wet places, foothills to
lower subalpine in s. and s.w. parts of MT. Also from
Ontario to AK and south to NM and CA. |
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(click on image for full size)
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ssp. foliosa var. andina:
(click on images for full size)
Varieties:
ssp. chamissonis var. interior: Pappus tawny, slightly feathery, leaves usually toothed, hairs at the base of the involucre with very prominent cross-walls.
ssp. foliosa: Pappus straw-colored or whitish, merely barbed, leaves with small teeth to more often entire; hairs at the base of the involucre with less prominent cross-walls.
ssp. foliosa var. andina: Plants less robust and with narrower (seldom over 4 cm wide) leaves.
ssp. foliosa var. maguirei: Plants exceptionally robust, up to 1 m tall, with large (up to 6 or 8 cm wide) leaves; a striking local form in the vicinity of Lower St. Mary Lake, Glacier Co., MT. |
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