THISTLE FAMILY 863 



15mm. long. Aplopappus integrifolius Porter. Meadows: Sask. Colo. B.C. 

 Plain Submont. Jl-Au. 



12. P. scaberula Greene. Stems erect, 3-6 dm. high, hirsute-villous; basal 

 leaves 1-1.5 dm. long, lanceolate, entire, hirtellous, reticulate; stem-leaves lance- 

 linear, sessile; involucres about 15 mm. high; bracts lanceolate, acute, scabrous- 

 ciliolate and sometimes slightly puberulent; ligules about 1 cm. long. Hills: 

 Ida. Submont. Jl. 



13. P. lanceolata (Hook.) Greene. Stems 2-4 dm. high, glabrous or nearly 

 so; basal leaf-blades lanceolate, usually more or less dentate, glabrous; stem- 

 leaves narrowly lanceolate, sessile; heads several, corymbose; involucres 15-20 

 mm. broad; bracts lanceolate, long-acute; ligules about 10 mm. long. A. lanceo- 

 latus T. & G. Meadows and flats: Sask. Neb. Wyo. B.C. Plain. Jl-Au. 



14. P. lagopus Rydb. Stems decumbent, 1-2 dm. long; basal leaves 6-10 

 cm. "long, lanceolate or linear-lanceolate, firm, distantly serrate with almost 

 spinulose teeth; stem-leaves narrowly linear-lanceolate, sessile; involucre about 

 12 mm. wide; bracts oblong, acute; ligules about 8 mm. long. Dry plains and 

 alkali flats: Wyo. Colo. Plain Submont. Jl-Au. 



15. P. Vaseyi (Parry) Rydb. Stems several, decumbent at the base, 1-3 

 dm. high, glabrous or nearly so; basal leaves 7-10 cm. long, lanceolate, sinuate- 

 dentate or entire; stem-leaves linear or lance-linear, sessile, mostly entire; invo- 

 lucres about 1 cm. broad; bracts lanceolate or oblong, abruptly acute; ligules 

 about 8 mm. long. A. lanceolatus Vaseyi Parry. Mountains: Sask. Colo. 

 Utah. Submont. Mont. Jl-S. 



16. P. tenuicaulis (D. C. Eat.) Greene. Stems decumbent at the base, 1-3 

 dm. high, glabrous, but usually with a villous tuft at the base; leaves narrowly 

 linear-lanceolate or linear, entire; inflorescence racemose; involucre somewhat 

 turbinate, 6-7 mm. high; bracts acute; ligules 4-5 mm. long. A. lanceolatus 

 tenuicaulis A. Gray. Alkaline meadows: Ore. Nev. Utah Wyo. Son. Jl- 

 Au. 



17. P. acuminata Rydb. Stems several, slender, about 1 dm. high, mono- 

 cephalous; leaves narrowly linear-oblanceplate, with strong midrib, 2-4 cm. long, 

 entire-margined, finely villous on both sides; heads on naked peduncles, about 

 1 cm. high and 12-15 mm. broad; bracts broadly lanceolate; ligules about 1 cm. 

 long. Hills: Wyo. 



18. P. inuloides (Nutt.) Greene. Stems 1-3 dm. high, ascending or de- 

 cumbent, more or less white-villous; lower leaf-blades lanceolate, or oblanceolate, 

 1-1.5 dm. long, usually more or less dentate; stem-leaves lanceolate or linear, 

 sessile; involucres 15-20 mm. wide; bracts linear, acuminate. P. crepidinea, P. 

 hololeuca, atod P. sericea Greene. Plains and meadows: Mont. Colo. Utah- 

 Ida. Submont. Mont. Je-Au. 



19. P. uniflora (Hook.) Greene. Stems ascending or decumbent at the base, 

 1-3 dm. high; basal leaf-blades lanceolate, usually sharply dentate; heads usually 

 solitary; involucres 15-20 mm. wide; bracts linear, acute, glabrous or slightly 

 villous; ligules about 8 mm. long. A. uniflorus T. & G. P. tuberosa and P. plan- 

 taginea Greene. River valleys : Sask. Colo. Utah Mont. Plain Mont. Jl-S. 



20. P. hirta (A. Gray) Greene. Stems ascending or decumbent at the base, 

 1-4 dm. high, hirsute-villous; basal leaves petioled, 1-2 dm. long, lanceolate, 

 coarsely and saliently dentate; heads solitary or few; involucres 15-20 mm. 

 broad; bracts linear, acuminate, glandular-pubescent, imbricate, but nearly 

 equal. A. hirtus A. Gray. P. foliosa Greene. Hills: Ore. Ida. Wash. Plain. 

 Submont. Jl. 



19. STENOTOPSIS Rydb. 



Low shrubs, with fastigiate branches, narrow fasciculate glandular-punctate 

 leaves and large peduncled heads. Involucre broadly hemispherical; its bracts 

 subequal, almost in a single series, linear-lanceolate, thin, scarious-margined, not 

 at all herbaceous. Receptacle naked, alveolar. Ray-flowers about 12, pistil- 

 late and fertile; ligules yellow, large. Disk-flowers perfect; corollas tubular 



