434 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



* Arnica gracilis Rydberg, Bull. Torr. Bot. Club, 24: 297. 



Resembles a depauperate A. latifolia^ but its basal leaves are 

 broadly ovate, not cordate, the head is smaller, the involucre glandu- 

 lar-puberulent, and the leaves and stem glabrate. It grows on moun- 

 tain-sides, at an altitude of 2000-3000 m. 



Montana: Spanish Peaks, 1896, Flodman, goi ; Spanish Basin, 

 June 28, 1S97, Rydberg & Bessey, 322^; Cedar Mountain, July 16, 

 1897, 5231 ; Pony, July 7, 5232 • Lake Plateau, 1897, P. Koch, 57. 



* Arnica amplexif olia : Arnica aniplcxicaulis Nutt. Trans. Am. Phil. 



Soc. (II.) 7 : 408, 1841 [Gray, Syn. Fl. i" : 381] ; not Wall., 1837. 

 Distinguished from the following species b}' its large half-clasp- 

 ing stem-leaves. It is found only in the w^estern part of Montana. 

 Montana: Columbia Falls, Mrs. Kennedy, ig and 2^. 



Arnica Chamissonis Less. Linnaea, 6: 238 [Syn. Fl. i" : 381 ; Man. 



R. M. 205 : 111. Fl. 3 : 472 ; Bot. Cal. i : 416] . 



In rich soil in the valleys, at an altitude of 1000-2000 m. 



Montana: Park Co., 1887, Tzceedy, J2i : Columbia Falls, J/r5. 

 Kennedy, 2j : Little Belt Mountains, 1896, Flodnuin, 8gj. 



* Arnica mollis Hook. Fl. Bor. Am. i': 331 [Torr. &: Gray, Fl. N. 



Am. 2: 450; Bot. Cal. i: 415]. 



Differs from the preceding in its short and broad mostly entire 

 leaves, the lower of which are generally blunt, villous pubescence, 

 and larger heads. It grows in wet soil, at an altitude of 1500- 

 2500 m. 



Montana: Park Co., 1887, Tzvccdy,j2j: Gallatin Co., 1886, 

 Tweedy. 



Yellowstone Park : Yellowstone Lake, 1894, F. H. Burgle- 

 hmis, 364-; Pelican Peak, 1885, Tzveedy, 6Sj; and 684. 



Arnica longifolia D. C. Eaton, King's Exped. 5: 186 [Syn. Fl. i^ : 



382 ; Man. R. M. 205]. 



Among rocks, at an altitude of about 3000 m. 



Montana: Yogo, 1896, Flodnian, S84; Electric Peak, Aug. 18, 

 1897, Rydberg d: Bessey, 3226. 



Yellowstone Park: East Fork of the Yellowstone, 1885, 

 Tzveedy, 68 1. 



Arnica foliosa Nutt. Trans. Am. Phil. Soc. (II.) 7: 407 [Syn. Fl. i- : 

 382 ; Man. R. M. 205 ; Bot. Cal. i : 416]. 

 Fairly common in wei meadows, up to an altitude of 1500-2500 m. 



