THISTLE FAMILY 855 



Bracts strongly carinato and with coaspicuoiLs green tips. 

 Bracts acute; upper leav&s not much reduced. 



30. C. elegans. 

 Bracts obtuse; upper leaves much reduced. 



42. C. turbinatus. 

 Leaves Unear to lance-linear or oblanccolate, 2-8 mm. wide. 

 Bracts linear, oblong, or lanceolate. 



Bracts at least the outer ones with thick green tips. 



31. C. linifolius. 

 Bracts comparatively thin, not green-tipped. 



Bracts linear-lanceolate, very acute. 32. C. stenolepis. 

 Bracts oblong or lanceolate, the inner obtuse. 



Involucre not viscid; leaves liispidulous ciliate-dentate. 



33. C. glaucus. 

 Inflorescence densely viscid; leaves minutely denticulate. 



34. C. viscidiflorus. 

 Bracts ovate, oval, or the inner broadly elliptic, abruptly short-cus- 

 pidate. 35. C. latifolius. 



Leaves and stems decidedly puberulent. 



Leaves 3-6 mm. wide, rarely twisted. 36. C. lanceolatus. 



Leaves 1-2.5 mm. wide, usually twisted. 



Leaves 3-nerved; inner bracts Unear, acute; branches green or yellow- 

 ish. 37. C. puberulus. 

 Leaves 1-nerved, thick: inner bracts spatulate-oblong, rounded at 

 the apex ; branches wliite. 38. C. marianus. 

 Achenes glabrous. 



Bracts acutish; leaves filiform. 9. C. filifolius. 



Bracts rounded at the apex; leaves linear. 



Branches wliite-tomentose when young; corolla 7-10 mm. long. 



Leaves linear, naore or less involute; corolla-lobes deltoid-lanceolate. 



39. C. leiospermus. 

 Leaves linear-oblanceolate, not involute; corolla-lobes linear-lanceolate. 



40. C. glareosus. 

 Branches not tomentose; corolla 5-6 mm. long. 



Plant glabrous. 



Leaves Unear-oblanceolate. 41. C. Vaseyi. 



Leaves fiUform, the upper much reduced. 42. C. turbinatus. 



Plant decidedly puberulent; leaves narrowly linear. 



38. C. marianus. 



1. C. depressus Nutt. Undershrub, sitffruticose at the base; stem 1-2 dm. 

 high; leaves short, 0.5-1 cm. long, thick; inflorescence short and corymbiform; 

 heads few, about 1 cm. high; bracts 5-ranked in 4—5 series, puberulent, lanceo- 

 late, gradually cuspidate. Bigelovia depressa A. Gray. Plains: Utah — Colo. — 

 N.M. Plain— Submont. Jl-S. 



2. C. Bigelovii (A. Gray) Greene. A shrub, 3-10 dm. high; branches white- 

 tomentose at first, soon glabrate; leaves linear-filiform, 1-3 cm. long, white- 

 tomentulose when young, soon glabrate; involucres 10-12 mm. high; bracts 

 thin, lanceolate, tomentulose and arachnoid-ciliate, 5-ranked in 4 or 5 series. 

 B. Bigelovii A. Gray. Dry plains: Colo. — Tex. — e Ariz. — Utah. Son. — Sub- 

 mont. Au-0. 



3. C. pulchellus (A. Gray) Greene. A shrub 6-10 dm. high; branches gla- 

 brous, striate; leaves narrowly linear, 1-2 cm. long, glabrous or cUiolate on the 

 margins; involucres 10-15 mm. high; bracts 5-ranked in 5-6 series, lanceolate; 

 achenes sparingly pubescent or glabrous. B. pulchella A. Gray. Dry hills: 

 Kans.— Tex.— N.M.— Utah; n Mex. Son.— Submont. Au-S. 



4. C. Parryi (A. Gray) Greene. SufTrutescent perennial; branches erect, 

 3-5 dm. higli, white-tomentulous when young; leaves 3-7 cm. long, minutely 

 puberulent or glabrate; heads racemose-thyrsoid ; involucres about 1 cm. high; 

 bracts linear-lanceolate, attenuate. C. affinis A. Nels. B. Parryi A. Gray. 

 Hills and dry valleys: Wyo. — Colo. Submont. — Mont. Au-S. 



5. C. attenuatus (M. E. Jones) Rvdh. Low shrub, 1-3 dm. high; leaves 2-3 

 cm. long, erect, green; heads in small corymbs; involucres about 1 cm. long; 

 bracts narrowly lanceolate, gradually long-attenuate, arachnoid-ciliate on the 

 margins; corollas 10-12 mm. long. B. Hownrdii attennaln M. E. Jones. C. affinis 

 attenuatus A. Nels. Moimtains: Utah. Suhmo7it. — Mont. Au-O. 



6. C. Newberryi Rydb. Shrubby below, 2-4 dm. high; leaves slightly 

 tomentulose when young, 2-3 cm. long; bracts narrowly lanceolate, attenuate 

 into a long slender subulate spreading tip, carinate, slightly tomentulose and 



