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

Shasta County arnica, veiny arnica

Habit Plants 10–50 cm. Plants 20–60 cm.
Stems

(forming clumps) simple or branched among heads.

simple or branched (prominently ribbed; caudices woody).

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.

6–10 pairs, cauline (basal leaves withered by flowering; proximal cauline scalelike, middle leaves largest, distal reduced, bractlike) usually broadly sessile, rarely broadly petiolate;

blades (3- or 5-nerved, strongly reticulate-veined) ovate-elliptic to broadly lanceolate, 3–7 × 1.5–4 cm (firm), margins irregularly and coarsely serrate, apices acute to obtuse, faces: abaxial pilose, stipitate-glandular (especially on veins), adaxial glabrate to stipitate-glandular.

Involucres

usually narrowly turbinate, rarely narrowly campanulate.

turbinate-campanulate.

Ray florets

8–16, yellow.

0.

Disc florets

corollas yellow;

anthers yellow.

30–60;

corollas yellow;

anthers yellow.

Phyllaries

9–20, linear to narrowly lanceolate.

8–19, ovate to broadly lanceolate.

Heads

1–3(–5).

1.

Cypselae

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

pappi stramineous to tawny, bristles subplumose.

dark gray, 6–8 mm, densely hirsute (hairs duplex);

pappi white, bristles barbellate.

2n

= 57, 76.

= 38.

Arnica ovata

Arnica venosa

Phenology Flowering Jul–Sep. Flowering May–Jun.
Habitat Moist meadows and conifer forests, stream banks, late snow-melt areas, montane to subalpine Open, often disturbed, oak-pine forests
Elevation 200–3600 m (700–11800 ft) 400–1400 m (1300–4600 ft)
Distribution
from FNA
AK; CA; CO; ID; MT; OR; UT; WA; WY; AB; BC; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

Arnica venosa is known only from Shasta and Trinity counties.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 21, p. 372. FNA vol. 21, p. 376.
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. sororia, A. spathulata, A. unalaschcensis, A. viscosa
Synonyms A. diversifolia, A. latifolia var. viscidula
Name authority Greene: Pittonia 4: 161. (1900) H. M. Hall: Univ. Calif. Publ. Bot. 6: 174. (1915)
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