Studies on the Rocky Mountain Flora.— IV 



By P. A. Rydberg 



Arnica tomentulosa sp. nov. 



A 



slender horizontal rootstock. Stem 



villous, about 4 dm. high : leaves oblanceolate, obtuse, sessile or 

 the lower with short-winged petioles, denticulate, finely villous- 

 pubescent, almost tomentulose, with two pairs of stronger veins, 

 the larger 1 3 dm. long, somewhat yellowish : heads few, hemi- 

 spherical ; disk about 1 5 mm. high and 2 cm. broad : bracts ovate 

 or ovater-oblong, obtuse, villous, 12-16 in number: rays light 

 yellow, over 1 cm. long, 4 mm. wide. 



This species is nearest to A. mollis, but differs in the broad 

 obtuse involucral bracts. It grows at an altitude of about 2700 m. 



Wyoming: Buffalo Fork. i8q7. F. Tweedy. $22. 



" Arnica tenuis sp. nov. 



A 



Stem spar- 



ingly villous pubescent, about 2 dm. high, monocephalous : leaves 

 usually 3 pairs, sparingly villous when young, entire ; the lower 

 two pairs oblanceolate or spatulate, the upper lanceolate : involucre 

 turbinate-campanulate, villous, about 13 mm. high, 10-12 mm. 

 broad: bracts linear, 1— 1 . 5 mm. wide, green; rays orange, 16- 

 18 mm. long and 4 mm. wide. 



This species resemble^ A. gracilis in the size of the plant and 



form of the head, but the leaves are much narrower and the heads 



solitary. It is intermediate between that 

 It grows at an elevation of about 2200 m. 



fi 



Wyoming : Big-Horn Mountains, 1899, F. Tweedy, 20Q4.. 



"'Artemisia diversifolia sp. nov. 



A white tomentose perennial with horizontal rootstock. Stems 

 simple, leafy, white-tomentose, 5-10 dm. high : leaves densely to- 

 mentose on both sides, subsessile, 5-10 cm. long : the lower pin- 

 nately cleft into 3-5 narrowly lanceolate acuminate lobes, which are 

 directed forward : the upper entire, linear-lanceolate, passing into 

 the bracts of the inflorescence : inflorescence a narrow panicle, 

 1.5-3 dm. l° n g : heads numerous, conglomerate, sessile, 3-4 mm. 

 high and 3 mm. broad : bracts oblong or ovate-oblong, scarious- 



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