THISTLE FAMILY 943 



2. H. tomentosus Rydb. Biennial; stem 3-4 dm. high, leafy and branched 

 above ;^ leaves 5-7 cm. long, bipinnately divided into linear segments, 4-10 mm. 

 long; involucre densely woolly, somewhat turbinate, 8 mm. high and broad; 

 flowers yellow; corolla throat a little over 1 mm. long, broadly campanulate, of 

 about the same length as the lobes. Dry plains: s Utah. Son, 



3. H, scaposus Rydb. Perennial; stem almost naked, with 1-2 reduced 

 leaves, more or less densely tomentose; leaves mostly basal, 5-7 cm. long, bi- 

 pinnately divided into Unear segments, 3-10 mm. long, densely tomentose, 

 especially at the base; heads about 1 cm. high and broad; bracts obovate, with 

 yellowish or purplish scarious margins; corollas yellow; throat nearly 2 mm. long, 

 campanulate and longer than the lobes; squamellae of the pappus fully 2 mm. 

 long, longer than the tube of the corolla. Dry hills: N.M. — Utah — Nev, — Ariz. 

 Son, My-Jl. 



4. H. arenosus Heller. A white-tomentose perennial, with branched woody 

 caudex; stems several, 2-4 dm. high, densely tomentose, especially at the base, 

 2-4-leaved; leaves mostly basal, twice pinnately divided into linear-filiform 

 divisions 3-15 mm. long, 1 mm. wide; heads about 8 mm. high, 8-10 mm. broad; 

 bracts oblong, with narrow scarious margins, tomentose; corollas yellow; throat 

 nearly 2 mm. long; achenes long-silky; pappus rather short, about 1 mm. long, 

 but not hidden by the hairs. On dry hills: N.M. — Colo. — Ariz, Son. — Sub- 

 mont. My-Jl. 



5. H. cinereus Rydb. Perennial, with a cespitose caudex; stems about 2 

 dm. high, branched; leaves bipinnately divided into Unear segments 1-2 cm. 

 long and about 1 mm. wide, sparingly grayish tomentulose; heads 8-10 mm. 

 high, 10-12 mm. broad; bracts oblong-obovate, with narrow scarious margins; 

 corollas yellow; throat about 1.5 mm. long, broadly campanulate, longer than 

 the lobes; achenes loosely villous. H, ochroleucm Greene. Dry hills and plains: 

 Colo. — Utah. Sub?nont. — Subalp. My-Jl. 



6. H. filifolius Hook. Perennial; stem 2-3.5 dm. high, sparingly branched; 

 leaves similar to those of H. tenuifolius; heads few, 10-15 mm. broad; bracts 

 obovate-oblong, with broad scarious margins, tomentose; corollas bright yellow; 

 throat about 1.5 mm. long; achenes densely villous, the long hairs hidmg the 

 small pappus; squamellae less than 1 mm. long. On plains and praines; Alta.— 

 Sask.— Kans.— N. M .—Nev.— Wash. Plain— SuhmonL Je-S. 



7. H. luteus Nutt. Perennial; stem 1-2 dm. high, with a few reduced 

 leaves and few heads; basal leaves 2-7 cm. long, twice pinnately divided into 

 short lobes 1-5 mm. long; heads about 1 cm. high, 10-15 mm. broad; bracts 

 oblong, broadlv scarious-margined ; corolla yellow; throat about 1 mm. long; 

 achenes densely villous-hirsute; scales of the pappus short, about 0.5 mm. long. 

 Bad-lands and clay-hills: Wyo. SuhmonL— Mont. My-Jl. 



8 H. parvulus Greene. Perennial; stem 1-2 dm. high, scapiform, sUghtly 

 tomentose; basal leaves 5-8 cm. long, bipinnatifid, with narrowly Unear-filiform 

 divisions, 5-12 mm. long, grayish-tomentose ; stem-leaves few and smaU; mvo- 

 lucres turbinate, 6-7 mm. high and broad; bracts oblong-obovate, greenish yeUow, 

 sparingly tomentulose; coroUas browTiish yellow; throat cyUndro-campanulate, 

 ^ r^o rr.TYi Innrr nhnnt ^ times as lonff as the teeth: achenes short villous. Dry 



hills: Colo. SuhmonL Jl-Au. 



dm 



9. H. lugens Greene. Perennial; stem scapitorm, ^-6 , u- 



tomentulose; leaves bipinnatifid with filiform divisions, permanently white- 

 tomentose, 5-10 cm. long; stem-leaves small and few; involucres nearly 1 cm 

 hkh l"*-i5 mm. broad; bracts elliptic, the outer usually with purple-tinged 

 margins; coroUa-throat cyhndraceous, 3-4 mm. long, 3-4 tunes as long as the 

 lobes; pkppus-scales oblong-obovate, as long as the coroUa-tube. Dry ridges: 

 s Calif.— Utah— Ariz. Son,— SuhmonL My-Au. , , , 



10 H eriopodus A. Nels. Perennial; stem 3-10 cm. high, leafy; leaves 

 numerous* bipinnately divided into filiform divisions, sparingly tomentulose or 

 glXateT inv^^^^ about 1 cm. high and 12-15 mm, broad; bracts elliptic, 

 S^rfn^,^^^^^^ sometimes purplish; coroUa-throat about 3 mm. long, cyhndro- 



