MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 399 



leaves linear, 2-5 cm. long and about 2 mm. wide, finely strigose- 

 puberulent, distantly sinuose-denticulate ; panicle simple, its 5-7 

 heads 7-9 mm. high and about the same in diameter, somewhat 

 turbinate ; bracts oblong-lanceolate, acuminate, puberulent, more or 

 less tinged with red or purple and with a greenish median line and 

 tip, comparatively thin and only moderately spreading ; rays 5-7 mm. 

 long, rose or light purple ; pappus tawny ; achenes finely strigose. 



This is a somewhat abnormal species of Machaeranthera, on ac- 

 count of its thin and less-spreading involucral bracts, and in this re- 

 spect fully agrees with M. Shastoisis (Gray) Greene. In fact, the 

 two species agree so perfectly in the size and form of the heads and 

 the ra\'s, the form, structure and coloration of the bracts, etc., that 

 it is impossible to distinguish them by the heads alone. The differ- 

 ence is in the stem and leaves. M. linearis is a much stricter plant, 

 and its leaves are narrowly linear, acute and denticulate, while those 

 of M. Sliastcnsis are broadly spatulate, entire and mostly obtuse. 

 Grows at an altitude of 2500 m. 



Yellowstone Park: Aug. 6, 1885, G. W. Letterman (type, in 

 the Herbarium of Columbia University). 



Erigeron simplex Greene, Fl. Fran. 387 ; Erigeron uniforus Hook. 



Fl. Bor. Am. 2: 17, in part [111. Fl. 3: 385 ; Syn. Fl. i- : 207; 



Bot. Cal. i: 327 ; Man. R. M. 168] ; not L. 



Differs from the European and Arctic species in the broad white 

 pink or light purple rays and the white-woolly involucre. It grows 

 on alpine peaks, at an altitude of about 3000 m. 



'Montana: Park Co., 1887, Tzvcedy, j68 ; Old Hollowtop, Pony, 

 July 7, 1897, Rydbcrg d: Bessey, jioj; Indian Creek, ]\.\]y 22, 

 jio6; Mt. Blackmore, 1886, Tzvccdy, 1141; McDonald's Peak, 

 1883, Canby, 182; Little Belt Mts., 1883, Sci'ibner, pp; Spanish 

 Peaks, 1896, Flodnian, Sjj. 



Yellowstone Park : Mt. Holmes, 1884, Tweedy, 122; Electric 

 Peak, Aug. 18, iSg"] , Rydberg £■ Bessey, jioy ; 1885, Tzvecdy, yoj. 



Erigeron salsuginosus Gray, Proc. Km. Acad. 16: 93 [Syn. Fl. i- : 



208; Man. R. M. 169]. 



Wet meadows, at an altitude of 2000-2500 m. 



Montana: Park Co., 1887, Tzveedy, j6ga; 1887,^77,- Old Hol- 

 lowtop, Pony, July 7, 1897, Rydberg d- Bessey, jioj; Sheridan, 

 1892, J/r5. L. A. Fitch; Columbia Falls, 1892, i?. S. Williams, 

 4]j ; McDonald's Peak, 1883, Canby, 18 j ; Bridger Mts., 1896, 

 Flodman, 8^6 ; Spanish Peaks, S^y; Spanish Basin, 8^s- 



