39^ MEMOIRS OP' THE NEW YORK BOTANICAL GARDEN. 



Oreastrum Haydeni (Porter) ; Aster ■pidchellus D. C. Eaton, King's 

 Exped. 5: 143, 1871 [Syn. Fl. i- : 201; Man. R. M. 166] ; not 

 Willd., 1800; Aster Haxdciii Vo\-\.Q.x \ Hayden, Geol. Rep. 1871 : 



485- 



Dr. Gray included two distinct species in A. pitlc/icllns, viz., 

 Oreastrum alpigemiui (Torr. & Gray) Greene, with larger heads 

 and broadly oblanceolate leaves, and the present species, with linear 

 leaves. It grows on the higher mountains, at an altitude of nearly 

 3000 m. 



Montana: Park Co., 1887, F. Tzveedy, Jji ; Cook City, 1891, 

 Mrs. M. L. Alderson; Lake Plateau, 1897, P. Koch, jy: Little 

 Belt Mountains, 1883, Scribncr, 88. 



Yellowstone Park: 1873, C. C. Parry, i2j; 1884, Tweedy, 

 133- 

 Machaeranthera tanacetifolia (H.B.K.) Nees, Gen. & Sp. Ast. 225 



[111. Fl. 3: 384] ; Aster tanaceti'JoUiis H.B.K. Nov. Gen. & Sp. 



4: 95 [Syn. Fl. i': 206; Bot. Cal. i: 322; Man. R. M. 168]. 



On dry prairies, uj) to an altitude of 2500 m. 



Yellowstone Park: 1888, Dr. Chas. II. Hall. 



Machaeranthera canescens (Pursh) Gray, PI. Wright. 2 : 75 ; Aster 



caiieseens Pursh, Fl. Am. Sept. 547 [Syn. Fl. i' : 206: Bot. Cal, 



I : 322 ; Man. R. M. 167]. 



Dry plains and sandy soil, up to an altitude of 2500 m. 



Montana: Bozeman, 1895, Rydberg, 2814. 



Yellowstone Park: Yellowstone Lake, 1885, Tzveedy, 742; 

 Yellowstone Falls, Aug. 13, 1897, Rydberg & Bessey, j/op; C. C. 

 Parry, ij2. 



* Machaeranthera leucanthemifolia Greene, Pittonia, 3: 61: Aster 



Icucauthonifoliiis Greene, Er3'thea, 3: 119. 



Like the preceding, but taller, and apparentl}' glaucous, but 

 really finel}' puberulent under a lens : leaves spatulate, coarsely and 

 deeply serrate. On hills and bench-lands, up to an altitude of 2000 m. 



Montana: Silver Bow Qo., j\Irs. J. H. Moore; Forks of the 

 Madison, Juh^ 26, 1897, Rydberg & Bessey, jiio; Cliff Lake, 

 511 1 ; Great Falls, 1891, 7?. S. Williams, /jj. 



* Machaeranthera linearis. 



Perennial; stem about 1.5 dm. high, finely grayish pubescent, 

 more or less tinged with purple, strict, terete and slightly striate; 



