Rydberg : Studies on the Rocky Mountain Flora 23 



bluish purple, 12-1 5 mm. long, 2 mm. wide : achenes thin, oblong, 

 truncate : pappus of 2 subulate bristles, with a few intermediate 

 squamellae. 



It is nearest related to T. eximia, but has larger heads, is more 

 leafy, and even the upper leaves are oblanceolate. It grows at 



an altitude of 2500-3000 m. 



Colorado : Side of Veta Mountain, 1900, F. K. Vreeland, 

 639 (type); Veta Pass, 1900, Rydberg & Vreeland, 5404 and 



West 



Erigeron leucotrichus sp. nov. 



Perennial with a somewhat branching rootstock. Stems about 

 2 dm. high, sparingly villous below, more copiously so above : 

 basal leaves oblanceolate or spatulate, 3-5 cm. long, short-petioled, 



bright green and sparingly hairy : stem-leaves oblanceolate to 



linear, 1-2 cm. long ; head solitary ; involucre white -villous with 

 multiceptate hairs ; bracts very numerous, lanceolate, almost 

 black, acuminate with spreading tips : rays very numerous, about 

 6 mm. long and 1 mm. wide, light purplish pink or white. 



This species is nearest related to E. melanocephahis, but easily 

 distinguished from it by the white, not black, hairs of the involucre. 

 It diners from E. simplex in the taller habit, the larger heads and 

 the darker bracts of the involucre. It grows at an altitude of 



about 2500 m. 



Wyoming: Big-Horn Mountains, July, 1899, Frank Tweedy, 



200J. 



y 



Erigeron incanescens sp. nov. 



(?) Erigeron glabellus var. mollis A. Gray, Proc. Acad. Phil. 



1863 : 64, in part. 



A densely and finely cinereous pubescent plant with perennial 

 rootstock. Stem simple, 1.5-3 dm. high, mostly ascending, striate 

 densely pubescent, leafy : basal leaves oblanceolate or spatulate : 

 stem-leaves about 5 cm. long and 1 cm. wide, oblong, oblanceo- 

 late or the upper lanceolate, sessile and somewhat clasping : heads 

 1-4; disk about 8 mm. high and 15 mm. broad: bracts very nu- 

 merous in one series, narrowly linear, cinereous as the rest of the 

 plant ; rays pale blue or violet, very numerous, about 1 5 mm. long 

 and less than I mm. wide. 



From Dr. Gray's description, this species must have been in- 

 cluded in E glabellus var '. mollis; but all specimens that I have 



