876 CARDUACEAE 



Bracts oblong or oblong-linear, obtuse. 1. B. frondosa. 



Bracts narrowly linear, acute. 2. B. angusta. 



1. B. frondosa (Nutt.) A. Gray. Annual; stem 2-5 dm. high, glabrous or 

 nearly so; leaves linear or lance-linear, 3-8 cm. long, glabrous, ciliolate on the 

 margins; involucre about 8 mm. high, fully 1 cm. broad; bracts in 3 distinct 

 series; ligules about 2 mm. long, pinkish. Aster frondosus T. & G. Saline soil 

 and along streams: Wyo. Colo. Calif. Ore. Plain. Au-O. 



2. B. angusta (Lindl.) Britton. Annual; stems erect, branched, glabrous, 

 2-6 dm. high; leaves narrowly linear, 3-10 cm. long, glabrous, slightly ciliolate 

 on the margins; involucre 6-8 mm. high, 8-10 mm. broad; bracts in 2 series, 

 almost equal; ray-flowers reduced to the tube or with rudimentary ligules. A. 

 angustus T. & G. Saline ground: Sask. Wis. Mo. Utah Alta. Plain 

 Son. Jl-S. 



32. EREMIASTRUM A. Gray. 



Dwarf, depressed winter annuals. Leaves entire. Heads solitary. Invo- 

 lucres hemispheric or broader; bracts numerous, linear, nearly in a single series, 

 herbaceous, with hyaline-scarious fimbriate margins; receptacle flat. Ray-flow- 

 ers numerous, in a single series, pistillate; ligules white. Disk-flowers numerous, 

 perfect and fertile. Achenes obovate-oblong, compressed, 2-nerved. Pappus 

 of very unequal bristles, the outer setulose and scarcely longer than the pubes- 

 cence of the achenes. 



1. E. bellioides A. Gray. Winter annual; stem diffusely branched at the 

 base; branches decumbent, 3-10 cm. long, hispid; leaves linear-spatulate, entire, 

 5-15 mm. long, hispid; heads subtended by rosulate leaves; involucres 5-6 mm. 

 high, 8-10 mm. broad; bracts linear-lanceolate, hispid; ligules white or violet, 

 about 5 mm. long, dentate at the apex. Deserts: s Utah Ariz. Calif. L. Son. 

 Ap-Je. 



33. LEUCOSYRIS Greene. SPINY ASTER. 



Rush-like spiny plants, often woody at the base, with small linear or subulate, 

 often deciduous leaves. Involucres hemispheric; bracts well imbricate, in 3 

 series, subulate. Ray-flowers pistillate and fertile, with short white ligules. 

 Disk-flowers perfect; corollas yellow. Style-branches with triangular-subulate 

 appendages, much shorter than the stigmatic portion. Achenes glabrous. 



1. L. spinosa (A. Gray) Greene. Perennial, usually shrubby at the base; 

 stems 1-2.5 m. high, usually more or less spiny, striate, glabrous; cauline leaves 

 linear or oblong, deciduous; involucre 5-6 mm. high, about 8 mm. broad; bracts 

 subulate, in about 3 series, scarious-margined, shorter than the disk; ligules 

 white, 3-4 mm. long; achenes glabrous. Aster spinosus A. Gray. Banks of 

 streams: Tex. s Utah Calif.; Mex. L. Son. Je-S. 



34. XYLORRHIZA Nutt. HOLLY-LEAVED ASTER. 



Perennial caulescent herbs, with thick woody taproots and short caudices. 

 Leaves many, spinulose-tipped, entire or spinulose-toothed. Heads large, soli- 

 tary at the ends of the branches, radiate. Involucres hemispheric; bracts mostly 

 in 2 or 3 series, acuminate, herbaceous, carinate below. Ray-flowers pistillate; 

 ligules showy, white or pinkish. Disk-flowers perfect. Appendages of the style- 

 branches lanceolate, acute. Achenes oblong, compressed. Pappus fulvous, 

 simple, of rather few coarse bristles. 



Leaves not spinulose-toothed. 



Glabrous or nearly so. 1. X. glabriuscula. 

 More or less villous. 



Bracts only slightly unequal, linear-lanceolate. 



Leaves linear-oblanceolate, acute. 2. X. villosa. 



Leaves spatulate, cuspidate. 3. X. venusta. 



Bracts very unequal, the outer ovate or ovate-lanceolate. 4. X. Parryi. 

 Leaves spinulose-toothed. 



Plant 1 dm. or less high, with a short caudex. 



Ligules 8-10 mm. long. 5. X. color adensis. 



Ligules 15-20 mm. long. 6. X. Brandegei. 



Plant tall, shrubby. 7. X. lanceolata. 



