THISTLE FAMILY 981 



26. A. subplumosa Greene. Stem 3-8 dm. high, more or less villous and 

 somewhat glandular above; lower leaves oblanceolate, wing-petioled, 5-10 cm. 

 long, denticulate or entire; upper stem-leaves sessUe, lanceolate or oblanceolate; 

 heads 1-5; involucres hemispheric, 10-15 mm. high; bracts linear-lanceolate, 

 acute; achenes hirsute, rarely almost glabrous. A. Chamissonis longinodosa A. 

 Nels. A. subplumosa silvatica A. Nels., in part, a low form. Mountain meadows: 

 Mont. — Colo. — Utah. Mont. — Subalp. Je-Au. 



27. A. tomentulosa Rydb. Stem villous, about 4 dm. high; leaves ob- 

 lanceolate, obtuse, sessile or the lower with short-winged petioles, denticulate, 

 finely villous-pubescent, almost tomentulose, with two pairs of stronger veins, 

 the larger 13 cm. long, somewhat yellowish; heads few, hemispherical; involucres 

 about 12 mm. high and 2 cm. broad; bracts ovate or ovate-oblong, villous; rays 

 light yellow, over 1 cm. long; achenes sparingly hispidulous. (?) A. slricta A. 

 Nels. Mountains: Wyo. — Colo. Mont. Au. 



28. A. Chamissonis Lessing. Stem 4—6 dm. high, softly villous, very 

 leafj^; lower leaf -blades oblanceolate, tapering into winged petioles, which are 

 connate-clasping, usually with 5 stronger veins, 7-15 cm. long, denticulate or 

 entire; upper leaves lanceolate, sessUe; heads cymose-paniculate; involucres 

 hemispheric, about 1 cm. high, hirsute-villous; bracts narrowly linear-lanceolate; 

 achenes hirsutulous. Wet places: Sask. — Alont. — Ida. — B.C. Submont. Jl- 

 Au. 



29. A. rhizomata A. Nels. Stem 2-5 dm. high, densely short-tomentose ; 

 leaves 5-7 pairs, oblong-lanceolate, obtuse or acute, 6-9 cm. long, denticulate or 

 entire, densely tomentose, the lower tapering into winged petioles, which are 

 sheathing at the base, the upper sessile: heads 1-5; involucres 10-12 mm. high, 

 more or less viUous-tomentose; bracts obiong or oblong-lanceolate, obtuse or 

 acute; achenes sparingly hirsutulous. A. lanulosa Greene. A. exigua A. Nels., a 

 depauperate form. Valleys: Mont. — Colo.--Utah — -Ida. Mont. — Subalp. Jl- 

 Au. 



30. A. foliosa Nutt. Stem 3-6 dm. high, tomentose, slightly glandular- 

 puberulent in the inflorescence; leaves Unear or linear-lanceolate, denssly tomen- 

 tulose, entire or rarely denticulate, 5-10 cm. long, the lower petioled, the upper 

 sessile; heads 1-7; involucres about 8 mm. high, hemispheric, tomentose, at least 

 at the base ; bracts linear or lance-linear, acute ; achenes hispidulous. Wet places : 

 Mack. — Colo. — Utah — Alaska. Submont. — Mont. Jl-Au. 



31. A. ocreata A. Nels. Stem 2-4 dm. high, sparingly puberulent, some- 

 what glandular so above; leaves linear-lanceolate, entire, or sparingly denticu- 

 late, finely puberulent, but green, the lower tapering into petioles, more or less 

 sheathing, the upper sessile; heads 3-5; involucres somewhat turbinate, 7-9 mm. 

 high, finely puberulent; achenes glabrous or sparingly hispidulous. Valleys: 

 Mont. — Wj^o. — Utah. Plain — Submont. Jl-Au. 



32. A. celsa A. Nels. Stem 4-6 dm. high, sparingly villous, and glandular- 

 puberulent in the inflorescence; leaves 6-8 pairs, puberulent and glandular- 

 granuliferous, green, iinear-oblanceolate or Imear-oblong, the lower petioled, 

 with sheathing bases; upper leaves sessile, lanceolate; heads 3-5, corymbose- 

 cymose; involucres hemispheric, nearly 1 cm. high, villous as well as glandular- 

 puberulent; bracts hnear-lanceolate, acute; achenes sparingly hirsutulous. Per- 

 haps not distinct from the preceding. Wet meadows: Mont. — Colo. — Ida. 

 Submont. — Mont. Jl-Au. 



33. A. rubricaulis Greene. Stem 3-6 dm. high, villous, often tinged with 

 reddish purple ; leaves lanceolate, 8-15 cm. long, the lower tapering into winged 

 petioles, all thin, triple-ribbed, sinuate-dentate or -denticulate, short-pubescent 

 on both sides; heads many, paniculate; involucres about 1 cm. high, nearly 2 cm. 

 broad; bracts lanceolate, acutish, sparsely hirsute; ligules about 12 mm. long; 

 achenes hirsute; pappus brownish, plumose. Meadows: B.C. — Mont. — (? Alaska). 

 Submont. — Mont. Je-Au. 



34. A. Rydbergii Greene. Stem 2-4 dm. high, sparingly villous; basal 

 leaves oblanceolate, entire, petioled; stem-leaves 3-4 pairs, glabrate or sparingly 



