878 CARDUACEAE 



1. U* alba fNutt.) Rydb. Stems 2-5 dm. high, smooth, scabrous, or his- 

 pidulous; lower leaves linear-oblanceolate, 3-5-ribbed, 5-15 mm. long, firm, the 

 upper linear; involucres about 5 mm. high, 5-8 mm. broad; ligules 5-6 mm. long. 

 Inula alba Nutt. Aster ptarmicoides T. & G. Rocky banks and bluffs: Vt.— 

 N.Y. — Colo. — Sask. Plain — SubmonL Jl-S. 



2. U. lutescens (Lindl.) Rydb. Stem 2-4 dm. high, scabrous, at least 

 above; leaves similar to those of the preceding species; involucres 5-6 mm. high, 

 6-8 mm. broad; ligules about 8 mm. long. Diplopappus lutescens Lindl. Aster 

 ptarmicoides lutescens A. Gray. Banks and plains: III— Wis. — Sask. Plain, 

 Au-S. 



37. BUCEPHALUS Nutt. 



L 



Caulescent leafy perennials, with rootstocks. Leaves alternate, sessile, from 

 ovate to linear. Heads corymbose, radiate, middle-sized. Involucres cam- 

 panulate: bracts regularly imbricate in several series, ovate to lanceolate, not 



:gui 



Liun 



rous, perfect; corollas yellow. Style appendages subulate, acute, 

 or rarely oblong and obtuse. Achenes flat, hirsute or glabrate in age. Pappus 

 of white capillary bristles. 



;hin and acute. villous-cUiate on the mai 

 Dvate-oblong or broadly lanceolate: heads 



i_,eaves lanceolate; neads 8-10 mm. high. 2 E eleaans 



Bracts firmer, merely clliolate, the outer obtuse. . . y . 



Bracts \\ith more or l^s foUaceous tips; involucre and branches of inflorescence de- 



ciaedly glanaular, the leaves less so. 3 e wasatchensis 



Bracts without foliaceous tips; plant not glandular or very rarely so 



Inner bracts acute. 4 E alaucus 



AU bracts obtuse or rounded and mucronate at the apex. 5! E. formosus. 



1. E- Engelmannii (D. C. Eat.) Greene. Stem robust, 5-15 dm. high, gla- 

 brous or slightly puberulent; leaves thin, 5-10 cm. long, loosely veined; involu- 

 cres hemispheric; bracts ovate, acute or acuminate, purple-tinged, in 5 series, 

 puberulent on the back and ciliate on the margins; ligules white, fully 1 cm. long! 

 Aster Engelmannii D. C. Eat. Moimtains: Alta.— Colo. — Nev. — Wash. — B.c! 

 Submont. — Mont. Jl-S. 



2. E. elegans Nutt. Stem 3-10 dm. high, leafy, puberulent; leaves pale, 

 lanceolate, 3-5 cm. long, scabrous-puberulent; involucres campanulate; bracts 

 ovate, acute, purple-tinged, puberulent on the back, villous-ciliate on the mar- 

 gins; ligules about 8 mm. long, white. Aster elegans T. & G, Woody mountain 

 slopes : Mont.— Wyo.— Utah— Neb.— Ore. Submont.—MonL Jl-S. 



3. E. wasatchensis (M. E. Jones) Rydb. Perennial with a rootstock; stem 

 glabrous up to the inflorescence; leaves lance-oblong, acute, sessile, 4-6 cm. long, 

 rather pale, glandular-puberulent ; involucres 10-12 mm. broad; bracts lanceo- 

 late, acute; rays fully 1 cm. long, A. glaucus wasatchensis M. E. Jones. Moun- 

 tains: Utah. Mont. Au, 



4. E. glaucus Nutt. Stem branched, glabrous, 3-5 dm. high; leaves gla- 

 brous, glaucous, lanceolate, linear or oblong, acute, 3-7 em. long, reticulate- 

 venose; involucres about 6 mm. high and 8 mm. broad; bract ovate glabrous 

 slightly Clliolate on the margins; ligules violet or white, 8-10 mm ' lone; A 

 glaucus T. & G. Mountains: Wyo.— Colo.— Utah. Submont.—MonL Jl-S. 



5. E. formosus Greene. Stem glabrous, 3-5 dm. high; leaves' linear, glau- 

 cous, glabrous, scabrous on the margins; involucres about 6 mm high and 8 

 mm broad; bracts ovate or oval, strongly purple-tinged, minutely ciliolate; 

 hgules deep blue, about 1 cm. long. Mountains; Colo. Mmt. Au. 



38. ASTER (Tourn.) L. Aster. 



Perennial herbs, usually with a rootstock, rarely with a woody caudex. 

 Leaves alternate, various. Heads corymbose, paniculate, racemose or rarelv 

 solitary radiate. Involucres hemispheric or campanulate, or turbinate: bracts 

 imbricate in several series, herbaceous or with herbaceous tips; receptacle flat 



or 



