RYDBERG: Rocky MOUNTAIN FLORA 655 
has very narrow, linear outer bracts and usually purplish or bluish 
rays. A. Osterhoutii grows along ditches at an altitude of about 
1500 m. 
_ Cororapo: New Windsor, 1899, Osterhout 2506 (type); also 
1898, 9, and 1900, 2328. 
v Aster corymbiformis sp nov. 
About 3 dm. high; stem strict, branched above, pubescent on 
decurrent lines; leaves linear, 5-8 mm. long, s cabrous on the 
margins, otherwise usually perfectly glabrous, half-clasping ; in 
florescence leafy, corymbiform ; heads about 8 mm. high ; bracts 
linear-lanceolate, very acute, glabrous, rather firm, with an oblan- 
ceolate green tip, in about 3 series of nearly equal length; rays 
white or purplish, about 7 mm. long and I mm. wide. 
This is perhaps nearest related to A. paniculatus, but in habit 
reminding somewhat of A. adscendens. From the former it differs 
in the strict habit, the corymbiform inflorescence and the entire 
leaves. From A. adscendens it differs in the more numerous 
heads and the bracts, the outer of which at least are oblanceolate 
and obtuse in A. adscendens. 
Cotorapo: West Cliff, 1896, Shear 3460 (type); also 3873 
and 3879, Parlin, Gunnison Co., 1901, 4. H. Smith 114 and 
II6 (?). 
v Aster Tweedyi sp. nov. 
Perennial with a horizontal rootstock; stem simple, usually 
purplish, pubescent only on decurrent lines, about 4 dm. high ; 
leaves oblanceolate, acute, glabrous except the ciliate margin, 
rather firm, often 1 dm. long; the lower with a winged petiole ; 
the upper sessile and half clasping ; inflorescence paniculate, leafy ; 
heads about 1 cm. high; bracts in about 3 series, linear or ob- 
lanceolate, not very unequal in length, the outer mostly green and 
obtuse, the inner with green tips and midrib, whitish on the sides 
below ; rays rose or purple, 8-10 mm. long and 1.5 mm. wide . 
This species is related to A. adscendens but differs in the stouter 
habit, broader and firmer leaves and larger heads. It grows in 
valleys at an altitude of 1500-2600 m. 
Wyomine : Copperton, 1901, Zweedy 4096 (type); Big Horn 
Mountains, 1899, Tweedy 2523; Laramie, 1897, Elias Nelson 152, 
Cotoravo: Laramie River, Larimer County, 1897, Osterhout 
2518, 
