COMPOSITAE (COMPOSITE FAMILY) 573 



tapering upward, puberulent. [A. parvifolia Greene, PI. Baker. 3: 28. 1901; 

 A. coloradensis Rydb. 1. c. 32: 131* (?).] In the mountains of our range. 



6. Arnica subplumosa Greene, Pitt. 3: 104. 1896. Stems erect, 4-8 dm. 

 high, the internodes long, often 10-15 cm., exceeding the leaves or rarely 

 shorter; pubescence of two kinds, a short, dense, glandular puberulence and 

 some scattering white crisped hairs: leaves 3-5 pairs, denticulate; the lowest 

 oblong-ob lanceolate, 6-10 cm. long, on slender petioles often as long; the 

 upper pairs sessile by a broad base, ovate to oblong, 3-12 cm. long: heads 

 1-3, mostly single and long-peduncled, large; disk 15-20 mm. high, 20-30 

 mm. broad; rays 10-15, 20-30 mm. long, 6-8 mm. broad; involucral bracts 

 14-20, lanceolate, acute, shorter than the disk: achenes striate, nearly linear, 

 obscurely short-hispid, about 5 mm. long, equaling the sordid, subplumose 

 pappus. A. chamissonis, largely, as to our range. (A. chamissonis longino- 

 dosa A. Nels. Bot. Gaz. 30: 199. 1900; A. rivularis Greene, 1. c. 4: 163. 1900.) 

 Boggy stream banks in the mountains of our range and northwestward. 



6a. Arnica subplumosa sylvatica (Greene) A. Nels. Smaller throughout, 

 clammy glandular-pubescent, the internodes shorter than the leaves. (A. 

 sylvatica Greene, PL Baker. 3: 27. 1901.) Wet places in pine and spruce 

 woods. 



66. Arnica subplumosa macillenta (Greene) A. Nels. As tall as the species 

 but less stout, thinner leaved, and less glandular, the pappus scarcely less 

 plumose. (A, macillenta Greene, Pitt. 4: 161. 1900.) Stream banks at 

 lower stations. 



7. Arnica mollis Hook. 1. c. Softly villous, puberulent, or nearly glabrous, 

 2-4 dm. high: lower leaves broadly ovate or oblanceolate, obtuse, mostly 

 5-nerved, abruptly tapering into a short, margined petiole, more or less den- 

 tate: heads rather larger; the involucral bracts broadly oblong or narrower, 

 acute or obtuse, somewhat villous: rays light yellow: achenes lightly pubes- 

 cent or glabrate. A. chamissonis in part, but mostly A. latifolia as to our 

 range. (A. latifolia Gray, Bot. Cal. 1: 415. 1885; A. tomentulosa Rydb. 1. c. 

 28: 20. 1901.) Northern Wyoming and Montana to the Pacific States. 



8. Arnica rhizomata A. Nels. 1. c. 31: 409. June, 1901. Conspicuously 

 rhizomatous, the creeping rootstocks sheathing-bracteate at the nodes, giv- 

 ing rise at intervals to the erect leafy stems and a few fleshy roots ; pubescence 

 whitish, soft, almost arachnoid, minutely granular-glutinous underneath the 

 pubescence on the inflorescence; stems 2-5 dm. high: leaves 5-7 pairs, rather 

 uniformly distributed, oblong-lanceolate, obtuse to acute; the lowest pair 

 with short scarious-margined petioles, early deciduous; the next 1 or 2 

 pairs 6-9 cm. long, about 2 cm. broad, on short, margined petioles which 

 dilate at base to form the short sheaths; the upper pairs sessile, shorter: heads 

 3-5, 10-12 mm. high, or sometimes more numerous and then smaller; pedun- 

 cles mostly short, erect, the lateral often exceeding the terminal; involucre 

 campanulate, the bracts much shorter than the disk, narrowly oblong, ob- 

 tusish: corolla long-pubescent on the tube, sometimes a few straggling hairs 

 on the lobes: achenes linear, almost glabrous: pappus fulvous or dirty- white. 

 [A. bmulosa Greene, PL Baker. 3: 26. Nov., 1901.] In the mountains of our 

 range. 



9. Arnica foliosa Nutt.* Trans. Am. Phil. Soc. 7: 407. 1841. Stems from 

 slender horizontal rootstocks, slender, 3-4 dm. high, erect, leafy, more or 

 less finely granular-glandular and pubescent: leaves 6-10 pairs, ascending or 

 erect, broadly to narrowly lanceolate, entire, subacute or obtuse, smaller 

 upward, all but the uppermost much exceeding the short internodes; petioles 

 slender, dilated at the base and connate, the pair forming a sheath which in 

 the lowest leaves is 2-3 cm. long, the sheath and petioles gradually shorter 

 upward to about the middle of the stem where both become wholly absent: 

 heads 1 -several; if more than 3, mostly somewhat racemose; terminal head 



* A. exigua A. Nels. Bot. Gaz. 30: 202. 1900, may or may not be distinct from this. It is 

 dwarf, branched, and polycephalous, and with the pubescence of A. rhizomata. Shores of 

 Yellowstone Lake. 



