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nodding arnica, Parry's arnica

Lake Louise arnica, snow arnica

Habit Plants 15–50(–60) cm. Plants 5–20 cm.
Stems

simple or branched among heads.

simple.

Leaves

(2–)3–4 pairs, basal and cauline (basal usually withered by flowering, petiolate or subsessile, blades ovate or nearly round to oblong-ovate, much smaller than cauline; sterile rosettes often present, proximal cauline often crowded toward stems bases);

petiolate;

blades broadly to narrowly lanceolate, oblong-ovate, ovate-lanceolate, or round, 4–22 × 1–6 cm, (bases obtuse or cuneate to truncate) margins usually entire, sometimes sparsely denticulate, faces scantily to moderately pilose (hairs white), adaxial sparsely stipitate-glandular (distal cauline leaves sessile, extremely reduced, nearly linear to narrowly elliptic-lanceolate).

1–3 pairs, mostly cauline (shorter plants often with leaves crowed mostly toward bases);

petiolate;

blades elliptic, oblong, or ovate-lanceolate, 1.5–7.5 × 0.5–2 cm, margins usually entire, rarely denticulate or slightly undulate, apices usually obtuse, sometimes acute or acuminate, faces glabrous or hispidulous-puberulent, ± densely stipitate-glandular.

Involucres

turbinate to narrowly campanulate.

campanulate-turbinate.

Ray florets

usually 0 (sometimes peripheral florets pistillate; corollas yellow, laminae rudimentary).

7–10;

corollas yellow.

Disc florets

20–50;

corollas yellow (1 or more lobes sometimes expanded, giving appearance of laminae);

anthers yellow.

corollas yellow;

anthers yellow.

Phyllaries

8–20, linear to narrowly lanceolate.

10–20, narrowly lanceolate (stipitate-glandular).

Heads

(1–)3–9(–14; often nodding in bud).

usually 1, sometimes 2–3 (nodding at flowering).

Cypselae

brown to black, 4–7 mm, glabrous or sparsely stipitate-glandular to densely hirsute;

pappi usually stramineous, rarely tawny, bristles barbellate to ± subplumose.

brown, 3–5 mm, abaxially glabrous, adaxially sparsely hirsute or glabrous throughout, usually stipitate-glandular toward apices, sometimes densely stipitate-glandular throughout;

pappi white, bristles barbellate.

2n

= 38, 57, 76.

= 76, 95.

Arnica parryi

Arnica louiseana

Phenology Flowering May–Sep. Flowering Jul–Aug.
Habitat Open conifer forests to alpine meadows Exposed tundra slopes and calcareous rock slides
Elevation 500–3800 m [1600–12500 ft] 1800–2100 m [5900–6900 ft]
Distribution
from FNA
CA; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
AB; BC
[BONAP county map]
Source FNA vol. 21, p. 373. FNA vol. 21, p. 371.
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. ovata, 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. mollis, A. nevadensis, A. ovata, A. parryi, A. rydbergii, A. sororia, A. spathulata, A. unalaschcensis, A. venosa, A. viscosa
Synonyms A. angustifolia subsp. eradiata, A. parryi subsp. sonnei, A. parryi var. sonnei
Name authority A. Gray: Amer. Naturalist 8: 213. (1874) Farr: Ottawa Naturalist 20: 109. (1906)
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