Plants (5-)20-80 cm. Stems solitary to densely clumped, simple or branched among heads. Leaves 4-8(-10) pairs, mostly cauline; usually sessile (sometimes with partly connate-sheathing bases), sometimes petiolate (proximalmost); blades lance-elliptic, lanceolate, oblanceolate, obovate, or ovate, 4-12(-20) × (1-)2-6(-8) cm, margins subentire to dentate-serrate, apices usually acute, rarely obtuse, faces glabrate to pilose. Heads (1-)3-10(-20). Involucres narrowly campanulate to turbinate. Phyllaries 8-15(-19), narrowly to broadly lanceolate. Ray florets (5-)7-17(-20); corollas yellow. Disc florets: corollas yellow; anthers yellow. Cypselae brown, 4-8 mm, sparsely hirsutulous, stipitate-glandular; pappi tawny, bristles subplumose.

Stems mostly solitary, 2-5 dm from a long, nearly naked rhizome, spreading-villous and often glandular above, mostly glabrous below; lvs sparsely long-hairy or subglabrous, dentate or denticulate, the lower ones evidently petiolate, elliptic or oblanceolate, to 20 cm (petiole included) נ4 cm, the upper sessile and often more lance-ovate or lance-oblong, the stem appearing leafy; heads 1-3, campanulate, the disk 1.5-2 cm wide; invol 10-13 mm, spreading villous and stipitate- glandular, the bracts more strongly acuminate than in no. 1 [Arnica lonchophylla Greene]; rays 10-15, 1.5-2 cm; pappus-bristles tawny, subplumose; 2n=76 (apomictic tetraploid). Streambanks and other moist, protected places especially in acid soils; mts. of n. N.Y., N.H., and Me. to N.B. and the Gasp顰enins. of Que. July, Aug. (A. mollis, misapplied)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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