THISTLE FAMILY 917 



4. A. monocephala DC. Stem 5-10 cm. high; leaves of the rosettes cus- 

 pidatc-mucronate, S-15 mm. long, silky-tomentose beneath; stem-leaves linear, 

 5-10 mm. long; involucres about 5 mm. high and 8 mm. broad; bracts of the 

 (rare) staminate heads broadly ovate, obtuse or acutish, those of the pistillate 

 heads lanceolate, the outer obtuse, the inner acute or acuminate. Arctic-alpine 

 situations: Alaska — B.C. — Alta. Alp. Jl. 



5. A. chlorantha Greene. Stem 7-15 cm. high; basal leaves and those of 

 the rosettes mucronate or acutish, loosely floccose, densely and permanently so 

 beneath, 1.5-2.5 cm. long; stem-leaves oblong-Unear; heads 3-6, somewhat con- 

 glomerate; involucres about 7 mm. high; bracts of the pLstillate heads with dark 

 ohve-green tips, the outer obtuse, the inner acute or acmninate. Mountains: 

 B.C. Mont. Jl-Au. 



6. A. pulvinata Greene. Stem 5-10 cm. high, densely white-tomentose; 

 leaves of the rosettes densely white-tomentose on both sides, with loose villous 

 tomentum; stem-leaves oblanceolate or oblong, acute; heads 5-8, in a dense 

 cluster; bracts of the staminate heads bro^\^l, oblong and obtuse, those of the 

 pistillate heads similar, but the inner more lanceolate and acute. Mountains: 

 Alta.— Mont.— B.C. Mont.— Alp. Je-Au. 



7. A. albescens (E. Nels.) Rydb. Stem 1 dm. or less high, tomentose; 

 leaves of the stolons 4—8 mm. long, densely and closely white-tomentose, obovate; 

 stem-leaves oblanceolate; heads 3-5 in a dense subcapitate cluster; bracts ellip- 

 tic, obtuse, light brown or yellowish. A. pulvinata albescens E. Nels. Moun- 

 tains: Alta. — Mont. — Ida. Submont. — Subalp. Je-Jl. 



8. A. fusca E. Nels. Stem 1-1.5 dm. high, tomentose; leaves of the 

 rosettes 15-22 mm. long, white-tomentose, with a close silky pubescence; stem- 

 leaves linear or linear-oblanceolate ; heads 3-13, pedicellate, corymbose; bracts 

 of the pistillate heads eUiptic or oblong, obtuse, greenish bro'ft'n. Open woods: 

 Wyo. — Ida. Mont. Au. 



9. A. acuta Rydb. Stem slender, 5-12 cm. high; leaves of the rosettes 

 15-25 mm. long, 2-4 mm. wide; stem-leaves narrowly linear or linear-oblanceo- 

 late; heads 3-5, conglomerate, sessile; bracts of the pistillate heads lanceolate to 

 linear-lanceolate, dark greenish brown with shghtly lighter tips, the inner acute. 

 Mountains: Alta. Subalp. — Alp. Jl-Au. 



10. A. media Greene. Stem 5-10 cm. high, loosely tomentose; leaves of 

 the rosettes 1-2 cm. long; heads 4^7, densely conglomerate; bracts of the stam- 

 inate head elhptic and obtuse, very dark green, or the innermost sometimes with 

 whitish tips; outer bracts of the pistillate head oblong, obtuse, the inner lanceo- 

 late, acute. A. austromontana E. Nels. Higher peaks: Alta. — Colo. — CaUf. — 

 B.C. Alp.— Subalp. Jl-Au. 



11. A. mucronata E. Nels. Stem 5-12 cm. high, tomentose; leaves of the 

 rosettes oblanceolate or narrowly spatulate, 1-2 cm. long; stem-leaves oblong- 

 linear, acute; heads 4-8, conglomerate; bracts in both the pistillate and the 

 staminate heads oblong or eUiptic, obtuse, dark brownish green, the inner bracts, 

 especiall}- in the staminate heads, often with whitish tips. ^lountains and rocky 

 slopes: Alta. — Wyo. — B.C. Alp. — Subalp. 



12. A. Sansoni Greene. Stem 1-2.5 dm. high, slender; leaves of the rosettes 

 linear-spat ulate or oblanceolate, 1-2 cm. long; stem-leaves linear, acute or acum- 

 inate, erect; heads 8-10, cj-mose and pcduncled; involucres 6-7 mm. high and 

 nearly as wide; bracts of the pistillate heads oblong or lanceolate, the inner acute, 

 bro^\^lish below, dirty white, yellowish or j)inkish towards the apex, those of 

 the staminate heads oblong, obtuse. Hills and mountains: Alta. — INlont. — B.C. 

 Submont. Jc-Jl. 



13. A. flavescens Rydb. Stem about 1 dm. high; leaves of the stolons 

 broadly spatulate, about 1 cm. long, acute^ densely tomentose on both sides; 

 stem-leaves oblong or hnear; heads 4-8, in a dense subcapitate cluster; involucres 

 4-5 mm. high, 5 mm. broad; bracts isabel-colored or yellowish, in the staminate 

 heads broadly elliptic, in the pistillate heads oblong, in both obtuse. A. reflexa 

 E. Nels., in part. Dry hills: Mont. — Colo. — Wash. Submont. — Mont. My-Jl. 



