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. 

 Leaves merely grayish, or densely villous or tomentulose. 



Leaves broadly oblong to lanceolate . . . 8. A. rhizomata. 



Leaves mostly narrowly lanceolate . . . . 9. A. foliosa. 



Leaves grayish-green with a fine pubescence and often 



granular-glandular . . . .' . . 10. A. celsa. 



Growing in clumps or broad caespitose mats. 



Leaves long (7-15 cm.), often tapering to a slender acu- 



mination . . . . . . . . . 11. A. longifolia. 



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



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

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

 Stems more or less naked-pedunculate 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 on short-clustered slender pedun- 

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

 Lower stem leaves broad, very obtuse, decurrent on the 



petiole 7. A. mollis. 



Heads eradiate 16. A. Parryi. 



1. Arnica cordifolia Hook. Fl. Bor. Am. 1: 331. 1834 Stems 3-6 dm. 

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

 commonly 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; 

 involucre about 15 mm. high: rays about 2.5-3 cm. long: achenes somewhat 

 hirsute. In the mountains; Colorado to Montana 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 sparsely hirsute; the 

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

 blade 6-10 cm. long; stem leaves 3-4 pairs, ovate-lanceolate; the lower on 

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

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

 large heads, glandular-pubescent on the peduncles and the linear-lanceolate 

 involucral bracts: pappus obscurely scabro-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, 5-8 cm. long, on petioles as long; the cauline ovate or oblong- 

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

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

 somewhat turbinate, of about 10 thin and green elliptic-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: 

 platyphylla A. Nels. Bot. Gaz. 31: 407. 1901; A. grandifolia Greene, 1. c. 

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



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

 1-2 dm. high; whole plant glabrous, except a little glandular puberulence 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 12-15, oblong-lanceolate, acuminate: rays about 

 15 mm. long: achene almost glabrous. A. latifolia in part. In the mountains 

 of our range. 



5. Arnica pumila Rydb. Mem. N. Y. Bot. Card. 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 



