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diverse arnica, leaf arnica, sticky arnica, sticky-leaf arnica

bunch arnica, orange arnica, twin arnica, twin leopardbane

Habit Plants 10–50 cm. Plants 15–50 cm.
Stems

(forming clumps) simple or branched among heads.

(1 or relatively few) simple or branched.

Leaves

2–3(–4) pairs (basal 1–2 pairs usually withered by flowering, petiolate, petioles broadly winged, blades round-ovate, relatively small; sterile rosettes lacking), mostly cauline; petiolate (at least middle pair, petioles broadly to narrowly winged);

blades broadly deltate to ovate, 4–8 × 2–6 cm (middle pair largest), margins irregularly denticulate to coarsely dentate-serrate, apices acute, faces puberulent (hairs minute) and stipitate-glandular.

3–6 pairs, crowded toward stem bases (axils lacking tufts of brown wool); petiolate (petioles, at least basal, narrowly winged);

blades (with 3 or 5, prominent, subparallel veins) oblanceolate to narrowly oblong, 3.5–14.5 × 0.6–2.4 cm, margins usually entire, rarely denticulate, apices obtuse, faces uniformly hairy, stipitate-glandular.

Involucres

usually narrowly turbinate, rarely narrowly campanulate.

hemispheric.

Ray florets

8–16, yellow.

9–17;

corollas yellow-orange.

Disc florets

corollas yellow;

anthers yellow.

corollas yellow;

anthers yellow.

Phyllaries

9–20, linear to narrowly lanceolate.

13–20, usually narrowly, sometimes broadly, lanceolate.

Heads

1–3(–5).

1–5.

Cypselae

brown to black, 5–7 mm, sparsely to moderately pilose and stipitate-glandular;

pappi stramineous to tawny, bristles subplumose.

brown, 3.5–5 mm, densely hirsute, sometimes sparingly glandular as well;

pappi white, bristles barbellate.

2n

= 57, 76.

= 38.

Arnica ovata

Arnica sororia

Phenology Flowering Jul–Sep. Flowering May–Jul.
Habitat Moist meadows and conifer forests, stream banks, late snow-melt areas, montane to subalpine Prairies and grasslands to montane conifer forests
Elevation 200–3600 m (700–11800 ft) 500–1500 m (1600–4900 ft)
Distribution
from FNA
AK; CA; CO; ID; MT; OR; UT; WA; WY; AB; BC; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; ID; MT; NV; OR; UT; WA; WY; AB; BC; SK
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 21, p. 372. FNA vol. 21, p. 370.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Chaenactidinae > Arnica Asteraceae > tribe Heliantheae > subtribe Chaenactidinae > Arnica
Sibling taxa
A. acaulis, A. angustifolia, A. cernua, A. chamissonis, A. cordifolia, A. dealbata, A. discoidea, A. fulgens, A. gracilis, A. griscomii, A. lanceolata, A. latifolia, A. lessingii, A. lonchophylla, A. longifolia, A. louiseana, A. mollis, A. nevadensis, A. parryi, A. rydbergii, A. sororia, A. spathulata, A. unalaschcensis, A. venosa, A. viscosa
A. acaulis, A. angustifolia, A. cernua, A. chamissonis, A. cordifolia, A. dealbata, A. discoidea, A. fulgens, A. gracilis, A. griscomii, A. lanceolata, A. latifolia, A. lessingii, A. lonchophylla, A. longifolia, A. louiseana, A. mollis, A. nevadensis, A. ovata, A. parryi, A. rydbergii, A. spathulata, A. unalaschcensis, A. venosa, A. viscosa
Synonyms A. diversifolia, A. latifolia var. viscidula A. fulgens var. sororia
Name authority Greene: Pittonia 4: 161. (1900) Greene: Ottawa Naturalist 23: 213. (1910)
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