THISTLE FAMILY 929 



1-3; inv'olucres 1.5-3 cm. high, slightly tomentose; bracts lanceolate, the outer 

 foUaceous, exceeding the disk; hgules 2-4 cm. long, 4r-8 mm. wide. HiUs: B.C. — 

 Ida. — Calif. Submont. Ap-Je. 



4. B. Careyana A. Gray. Basal leaves long-petioled; blades cordate, entire, 

 somewhat grayish scabrous-puberulent, subcoriaceous, reticulate, 1-1.5 dm. 

 long; involucres 10-15 mm. high; bracts oblong-lanceolate or a few of the outer 

 lanceolate and longer, all firm and puberulent; Hgules broadly oval, 15-18 mm. 

 long, 8-9 mm. wide, becoming papery and persistent; style-branches of the disk- 

 flowers subulate and very hispid; achenes pubescent. Sandy plains: Ida. — Wash. 

 Son. My. 



5. B. incana Nutt. Leaves all basal, 1-1.5 dm. long, short-petioled, tomen- 

 tose, pimiately divided into ovate, entire or slightly toothed divisions 1-3 cm. 

 long; scape 1-2 dm. high; involucre floccose, 15-20 mm. high, 20-25 mm. broad; 

 bracts lanceolate, appressed or the outer with spreading tips; ligules 2-2.5 cm. 

 long, about 5 mm. wide. Dry hiUs: Wash. — Mont. — Wyo. — Calif. Plain — 

 Submont. My-Jl. 



6. B. floccosa Rydb. Leaves mostly basal, floccose on both sides, 2-3 dm. 

 long, regularly pinnately divided to near the midrib or some sometimes only 

 coarsely toothed; segments lanceolate, acute, 3-5 cm. long, coarsely toothed; 

 stem scapiform, 3-5 dm. high, villous, the upper portion densely floccose; invo- 

 lucre about 3 cm. broad; bracts numerous in several series, lanceolate, the outer 

 often spreading with recurved tips; Ugules 3-4 cm. long, about 1 cm. uide. Hill- 

 sides: Alont. — Wyo. — Ida. Plain — Mont. My-Jl. 



7. B. terebinthacea (Hook.) Nutt. Leaves mostly aU basal, short-petioled; 

 blades 1-2 dm. long, lanceolate in outline, some of them only incised-toothed, 

 others pinnately divided, hirsutulous-pubescent or glabrate; scape 1-3 dm. high; 

 involucre 15-20 mm. high; bracts lanceolate, almost equal. In stony grounds 

 and open woods: Ida. — ^\Yash.- — Ore. Submont. My-Je. 



8. B. macrophylla Nutt. Stem 4-6 dm. high, sparingly viUous-hirsute; 

 basal leaves 2-5 dm. long, petioled, most of them pinnately divided into lanceo- 

 late divisions, but some occasionally only toothed; involucre 25 mm. high and 

 2.5-4 cm. broad; bracts linear-lanceolate, loose and the outer reflexed; Ugules 3-5 

 cm. long, about 1 cm. wide. On drj' hUlsides: Utah — Wyo. Submont. My-Je. 



9. B. hirsuta Nutt. Stem scapiform, sparingly viUous-hirsute ; leaves 

 short-petioled, lanceolate in outline, pinnately divided ; divisions ovate or lanceo- 

 late, coarselj' toothed or again pinnatifid, strongly veined and rigid; involucre 

 about 1.5 cm. high and 2 cm. broad; bracts hnear-lanceolate, spreading, hirsute; 

 Ugules 15-20 mm. long, 4-6 mm. wide. On dry groimd: Utah — B.C. — Calif. 

 Submont. My-Je. 



72. WYETHIA Nutt. Mule-ears. 



Stout and low perennial herbs, with thick taproot, balsamic juice, and alter- 

 nate, commonly entire, pionately veined leaves. Heads solitary or few. Invo- 

 lucres hemispheric or flat; bracts more or less imbricate, the outer often foUaceous. 

 Ray-flowers pistiUate and fertile; Ugules yeUow. Disk-flowers hermaphrodite 

 and fertile; sU'les with slender, subulate hispid appendages. Paleae of the re- 

 ceptacle lanceolate, partly embracing the aclienes. Achenes prismatic, 4-angled, 

 somewhat flattened in the disk-flowers, or 3-angled in the ray-flowers. Pappus 

 a lacerate chaffy crown or of almost distinct squameUae. 



Involucral bracts nearly equal, in 2-3 series ; stem not white. 



Rays pale yeUow or white; plant hispid. 1. W. helianthoides. 



Rays bright yellow. 



Plant glabrous. 2. W. amplexicaulis . 



Plant pubescent. 



Plant sparingly hirsute or scabrotis. 3. W. robusta. 



Plant densely pubescent. 4. W. arizonica 



Involucral bracts unequal, the outer much shorter, in 5-6 series; stem white. 



5. W. scabra. 



1. W. helianthoides Nutt. Stem 2^ dm. high, more or less hirsute; leaves 

 with margined petioles, more or less hirsute; blades of the basal leaves oval or 



