24.
Arnica latifolia
Bongard, Mém. Acad. Imp. Sci. St.-Pétersbourg, Sér. 6, Sci. Math. 2: 147. 1832.
Broadleaf arnica
Plants
10—50 cm.
Stems
usually simple, sometimes branched distally.
Leaves
2—4(—6) pairs, cauline (basal leaves often persistent on sterile rosettes), petiolate (proximal, petioles relatively short, broadly winged) or sessile (mid and distal); blades lance-elliptic to ovate, 2—10 × 1—6 cm, margins serrate to dentate, apices obtuse to acute, faces glabrous or sparsely villous.
Heads
1 or 3—5(—9).
Involucres
narrowly turbinate.
Phyllaries
8—20, lanceolate to oblanceolate.
Ray florets
8—15; corollas yellow.
Disc florets
20—90; corollas yellow; anthers yellow.
Cypselae
dark brown, 5—9 mm, sparsely villous;
pappi
white, bristles barbellate.
2
n
= 38, 76.
Flowering Jul—Aug. Relatively moist, montane conifer forests to subalpine meadows; 500—3300 m; Alta., B.C., N.W.T., Yukon; Alaska, Calif., Colo., Idaho, Mont., Oreg., Utah, Wash., Wyo.
