572 coMPOSiTAE (composite family) 



Heads large, solitary, or often 3, rarely 5, stout-peduncled. ' 



Leaf-blades not decurrent . . . . . . 6. A. subplumosa 



Leaf-blades decurrent on the petioles . ; . . . 7. A. mollis. 

 Heads smaller, few to several, on rather short, slender 



pedicels, often crowded. i 



Leaves merely grayish, or densely villous or tomentulose. 



Leaves broadly oblong to lanceols^te . . . . 8. A; rhizomata. 



Leaves mostly narro^vly lanceolate . . . . 9. A. foliosa. 



Leaves grayish-green with a fine pubescence an'd' often 



granular-glandular . . . , . . 10. A, celsa. 



Growing in clumps or broad caespitose mats. 

 ,1 Leaves long (7-15 cm.), often tapering to a slendec acu- , . i 



. , , mipation ; 11. A. longifolia. 



Leaves' shorter (3-7 cm.), oblong-lanceolate. 



Rays orange; achenes sparsely hispidulous '^ . .' . ' 12. A. arcana. 

 Rays lemon-yellow; achenes white, feilky-villous . . 13. .A. Rydbergii. 

 Stems more or less naked-ped^unculate upward. 

 Leaves lanceolate to linear. 



Heads large, long-pedunculate, usually solitary but often 



3-5; involucral bracts green ..... 14. A. fulgens. 



Heads smaller, mostly 5 oh short.'clustered slender pedun- 

 cles; involucral bracts purple-tipped .... 15. A. stricta. 



Lower stem leaves broad, very obtuse, decurrent on the . 



petiole . . , . . . . . . . . 7. A. molUs. 



Heads eradiate j . . , . . . ' . . . . 16. A. Parryi. 



1. Arnica cordifolia Hook. Fl. Bor. Am. 1: 331. 1834. Stems ^6 dm. 

 high, from dreeping rootstocks; herbage pubescent, the stems and peduncles 

 commpnly hirsute or villous: lower leaves long-petioled, deeply cordate to 

 ovate, obtuse, dentate; upper leaves small, sessile: heads either solitary and 

 terminating the simple stem or several and long-peduncled in a loose cyme; 

 ihVoljicre about 15 inin. high: rays about 2.5-3 cm. long: achenes somewhat 

 hirsute. — In the mountains; Cblorado to ^lontana and west to the Sierras. 



2. Arnica paniculata A. Nels. Stems rather stout, 4-7 dm. high, granular- 

 puberulent and sparsely ciliate-hirsute: leaves softly and spairsely hirsute'; the 

 radical long-petioled, triangular-lanceolate, mostly with cordate base, the 

 blade 6-10 cm. long; stem leaves, 3r4,, p^irs,. qvate-lanceolate; the lower on 

 petioles longer than the blades, smaller and shorter petioled (or sessile) up- 

 ward: inflorescence an open fpliar-bracted panicle of several to many rather 

 large heads, glandular-pubescent on the :pedimcles and the linear-lanceolate 

 involucral bracts: pappus obscurelyiscabro-plumose: achenes dark; with short, 

 sparse pubescence. — Mountains of southern Wyoming. 



3. Arnica ventorum Greene, Pitt. 4: 173. 1900. Stems 2-4 dm. high,! 

 slender, with thin and delicate glabrous foliage: radical' leaves orbicular to 

 cordate-ovate, 6-8 cm. long, on petioles as long ;> the cauline ovate or oblong- 

 ovate, mostly in 2 pairs only, sessile; all repand-dentioulate, delicately cilio-. 

 late, otherwise glabrous: heads 1-3, long-peduncled; involucres narrow and 

 somewhat turbinate, of about 10 thin and green eUiptic-lanceolate, acuminate, 

 ciliolate, and slightly glandular-puberulent bracts: rays rather few, deep yel- 

 low, 7-nerved, 3-dentate, the middle tooth notably larger than the other two: 

 achenes glandular-scabrellous; pappus fine, white. 'A,'latifolia in part. [A. 

 plat'ffphylla A. Nels. Bot. Gaz. 31: 407. 1901; A. grandifolid Greene, 1. c. 

 172' (?).] — Subalpine; Colorado to Montana and northwestward. 



4. Arnica graciUs Rydb. Bull. Torr. Bot. Club 24: 297. 1897. Stem slender, 

 1-2 dm. high; whole plant glabrous, except a little glandular puberulfslice on 

 the pedicels and involucre: basal leaves broadly ovate, petioled; dentate, 

 3-ribbed; stem leaves about 2 pairs, similar, the upper sessile: heads 1-3; 

 disk 10-15 mm. high; bracts 12-16, oblong-lanceolate', acuminate: rays about 

 15 mm. long: achene almost glabrous. A. latifoliain part. — In the mountains 

 of our range. ' " " ' ' , 



5. Arnica pumila Rydb. Mem. N. Y. Bot. Gard. 1: 432. 1900. Stem low, 

 generally 1-2 dm., seldom 3 dm. high, more or less hirsute, and the upper 

 portion somewhat woolly and glandular: leaves .comparatively firm, ovate, 

 the basal ones petioled; stem leaves 1-2 pairs, very short-petioled or sessile; 

 all puberulent : head turbinate or campanulate, about 2 cm.'high ; bracts oblong- 

 lanceolate, acute, puberulent and slightly villous at the base:, achenes slightly 



