CHICORY FAMILY 1023 



with 15 subequal ribs; outer persistent pappus-bristles often wanting, sometimes 

 1 or 2. Dry sandy slopes: Wyo. — ^Colo. Son. — Submont. Je. 



3. M. Torreyi A. Gray. Annual; stem branched at the base, 1-2 dm. high, 

 with decumbent branches, glabrous or sparingly glandular in the inflorescence; 

 leaves obovate in outline, runcinate-pinnatifid, with oblong or lanceolate, di- 

 vergent toothed, lobes; heads paniculate; involucres about 1 cm. high; achenes 

 linear-cylindric, with 5 of the angles wing-margined; outer pappus of 2-5 persistent 

 bristles. Low ground: Ore. — -Utah— Calif. Son. Je. 



4. M. sonchioides (Nutt.) T. & G. Annual; stem branched at the base, 

 with ascending branches; leaves oblanceolate or obovate in outline, lyrate-pinnat- 

 ifid, with oblong, dentate lobes; heads paniculate; involucres 8-10 mm. high; 

 bracts in 3 series, the outer ovate-lanceolate, the inner linear-lanceolate; achenes 

 cylindric, 15-ribbed, with 5 ribs, but slightly stronger, not winged; outer per- 

 sistent bristles usually none. Plains: Neb. — ^Ivans. — s Calif. — Nev. — Ida. Son. 

 My-Je. 



16. PLEIACANTHUS (Nutt.) Rydb. 



Diffuse and spinescent perennials, suffruticose at the base, with flexuose 

 branches. Lower leaves linear, entire, the upper reduced to scales. Involucre 

 cjdindric; bracts 3-5, linear, with 1-3 minute calyculate ones at the base. Flow- 

 ers 3-5, rose-colored. Achenes prismatic, 4- or 5-ribbed, truncate at the apex. 

 Pappus of rather few rigid, unequal bristles, falling off separate. 



1. P. spinosus (Nutt.) Rj^db. Lower leaves linear, the upper leaves scale- 

 hke, lanceolate, 2-5 mm. long; heads lateral, short-peduncled ; calyculate bracts 

 ovate, more or less imbricate; bracts proper, ovate-lanceolate. Lygodesmia 

 spinosa Nutt. Gravelly hills and plains: Mont. — Ariz. — Calif. — B.C. Plain — 

 Submont. Au-S. 



17. LYGODESMIA D. Don. Wild Asparagus, Skeleton Weed, 



Prairie Pink. 



Rush-like herbs, with narrow alternate leaves. Involucre cylindric; bracts 

 5-12, linear, equal, with a few calyculate ones at the base. Flowers 5-12, pink 

 or rose-colored. Achenes slender, 4-8-ribbed, slightly tapering towards the sum- 

 mit. Pappus of numerous soft bristles, falling off separate. 



Perennials, with deep-seated rootstocks. 



Involucres 1.5-25 nun. liigli, 6-10-flowered. 1. L. grandiflora. 



Involucres 10 nim. high, usually 5-flowered; upper leaves reduced. 2. L. juncca. 



Annuals; involucres 10-1,5 nun. high. 3. L. rostrala. 



1. L. grandiflora (Nutt.) T. & G. Stem simple below, 1-4 dm. high, leafy; 

 leaves narrowly linear, ascending, 5-10 cm. long; calyculate bracts ovate, 2-3 

 mm. long; bracts proper narrowly linear; achenes about 1 cm. long; pappus sor- 

 did. Gravelly hills: Wyo. — Colo. — Ariz. — -Ida. Son. — Submont. My-Jl. 



2. L. juncea (Pursh) D. Don. Stem 2-4 dm. high, much branched from 

 near the base; lower leaves linear, 2-10 cm. long, those of the branches reduced 

 and subulate; involucres 10-12 mm. high; calyculate bracts lanceolate, 1-2 mm. 

 long; bracts proper 5, narrowly linear; achenes 5-6 mm. long; pappus sordid. 

 Plains and prairies: Minn.— Mo, — N.M. — Nev. — Alta. Plain — Submont. Je- 

 Au. 



3. L. rostrata A. Gray. Stem erect, 3-10 dm. high, with strongly ascending 

 branches; leaves narrowly linear, obscurely 3-nerved, 5-20 cm. long; heads 

 numerous, ending short scaly branches; calyculate bracts lanceolate, 2-3 mm. 

 long; bracts proper 8-9, narrowly linear; flowers as many; achenes fusiform, 

 5-8-striate; pappus dull white. Caiions and sandy plains: Sask. — Kans. — Colo. 

 Plain. Jl-S. 



18. PRENANTHELLA Rydb. 



Low diffusely branched annuals, with numerous small heads terminating the 

 branches. Lower leaves ample, more or less runcinate, the upper reduced and 

 bract-like. Involucres oblong, 4^5-flowered, with as many oblong bracts and 



