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 pvibescent. 



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. 9- 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. fulgent. 



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. i/- 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. 



