388 CARDUACEAE. 



Stem leafy and usually with several heads ; stem-leaves not much reduced. 

 Leaves grayish, densely villous or tomentulose. 

 Pubescence of the leaves soft and villous. 



Leaves broadly oblanceolate or lanceolate. 5. A. rhisomata. 



Leaves linear or linear-lanceolate. 6. A. foliosa. 



Pubescence of the leaves very short and fine ; leaves linear-lanceolate. 



7. A. celsa. 

 Leaves green, not densely pubescent. 



Plant sparingly hirsute or glabrate ; leaves usually broad. 



Involucres and peduncles pilose or villous, not at all glandular or viscid. 

 Stem tall, 4-6 dm. high; involucres hemispherical. 



8. A. macilenta. 

 Stem low, 1.5-3 dm. high, few-leaved; involucre turbinate or cam- 



panulate. g. A. Rydbergii. 



Involucres and peduncles hirsute and glandular. 



Bracts oblanceolate. n. A. coloradensis. 



Bracts linear-lanceolate 12. A. subplumosa. 



Plant minutely glandular puberulent ; leaves linear-lanceolate. 



13. A. longifolia. 



Stem with a few more or less reduced leaves and usually a single head. 

 Basal leaves not with a tuft of brown hairs at the bases. 



Involucres turbinate, as well as the peduncles densely villous, scarcely 



at all glandular ; stem glabrous or nearly so below. 

 Leaves strongly 3-nerved. 9. A. Rydbergii. 



Leaves faintly 3-nerved. 10. A. tenuis. 



Involucres hemispherical, as well as the peduncles more or less glandular ; 



stem pubescent throughout. 

 Involucres densely hirsute and glandular. 



Stem-leaves linear. 14. A. fulgens. 



Stem-leaves ovate-lanceolate. n. A. coloradensis, 



Involucres glandular-puberulent. 7. A. celsa. 



Basal leaves with a dense tuft of brown hairs at their bases. 



Leaves linear. 15. A. pedunculata. 



Leaves oblong, lanceolate or oblanceolate. 16. A. monocephala. 



Heads discoid. 17. A. Parryi. 



1. Arnica platyphylla A. Nels. In the mountains of Mont, and Ida. to 

 Colo. Ragged Mountain. 



2. Arnica silvatica Greene. On wooded mountains from Mont, to Colo. 

 Alt. 9000-12,000 ft Ruby; Mt. Bartlett; Robinson. 



3. Arnica pumila Rydb. (A. parvifolia Greene) On the mountains from 

 Wyo. to Colo, and Utah. Alt. 8000-11,000 ft. Westcliffe ; hills about Box 

 Canon, west of Ouray; Red Mountain, south of Ouray; Veta Pass; Valley 

 Spur; Mt. Hesperus ; Marshall Pass; Gray's Peak. 



4. Arnica cordifolia Hook. On wooded hills from Mont, and B. C. to Colo, 

 and Calif. Alt. 6000-11,000 ft. Rist Canon; mountains about Ouray; foot- 

 hills, Larimer Co.; Bear Creek divide, west of Mt. Hesperus; Silver Plume; 

 near Pagosa , Peak ; Wahatoya Canon ; mountain near Veta Pass ; East Indian 

 Creek; Chambers' Lake; foot-hills west of Ft. Collins; Silverton; Lake Mo- 

 raine; Canon City; Tennessee Pass, Lake Co.; Carson; Villa Grove; Eldora 

 to Baltimore; Berthoud Pass; between Sunshine and Ward; Stove Prairie 

 Hill; Horsetooth Gulch; Long Gulch; Clear Creek Canon; Massif de 1'Arapa- 

 hoe; near Denver; Lake City. 



5. Arnica rhizomata A. Nels. (A. lanulosa Greene) In valleys from Mont, 

 and Ida. to Colo. Alt. 8000-11,000 ft Banks of Elk River, Routt Co.; on 

 Grizzly Creek; Marshall Pass; Robinson; below Grand Lake; Twin Lakes; 

 Crested Butte. 



