1006 CARDUACEAE 



M 

 J 



Spines of the middle bracts stout and ascending. 



Upper leaves entire or with shallow lobes; involucre less than 2 cm. 



Inroad, very dark. 49. C. canescens. 



Upper leaves deeply pinnatifid; involucres about 3 cm. broad, light 

 colored, except the viscid ridge. 50. C. pulcherrimum. 



Spines of the middle bracts 5 mm. long or less, weak and spreading. 



Leavas, at least the upper ones, entire or slightly lobed, tomentose on both 

 sides. 51. C oblanceolatum. 



Leaves piunately divided or deeply lobed. 



Leavas deeply pinnatifid, with narrow, linear-lanceolate lobes; plant 



yellowish. . 52. C. Flodmanii. 



Leaves with triangular or ovate-lanceolate lobes. 



Bracts with very inconspicuous glandular ridge, not at all viscid. 



53. C. floccosum^ 

 Bracts with a conspicuous glandular ridge, surrounded by a viscid 



area. 

 Leaves tomentose on both sides. 54. C, undulatum.^ 



Leaves glabrate and dark green above. 55. C Engelmannii . 

 Involucres 4-7 cm. in diameter. 



Spines of the involucral bracts rarely more than 5 mm. long; leaves not con- 

 spicuously decurrent. 5G. C. megacephalum. 

 Spines of the middle bracts fully 1 cm. long; leaves narrower, conspicuously 

 decurrent. 57. C. ochocenirum. 

 Leaves greenish and sparingly floccose on both sides; bracts linear-lanceolate, very viscid, 

 with stout erect or ascending spines. 41. C canovirens. 



XL ARAT:xsrA. 

 One species. 58. C. arvense. 



1. C. Parryi (A, Gray) Petrak. Stem 3-10 dm. high; lo\\er leaves petiolcd, 

 oblanceolate, 2-4 dm. long, stem-leaves lanceolate or linear in outline, sessile, 

 with auriculate-clasping bases, more or less lobed with triangular teeth and weak 

 spines; heads several, spicately-glomerate, leafy-bracted, 2-3 cm. high; outer 

 bracts with weak spines, the inner mostly vnth lanceolate-erose tips, spineless. 

 Cnicus Parryi A. Gray. Carduus viridifiorus Greene. Mountains: Colo. — 

 Utah — N.M . — Ariz. Suhmont. — Siibalp. 



2. C. araneans Rydb, Stem slender, about 5 dm. high, shghtly arach- 

 noid; leaves linear in outUne, 10-12 cm. long, slightly arachnoid or glabrate and 

 bright green above, grayish tomentose beneath, pinnatifid, with oblong, moder- 

 ately strongly spine-tipped lobes; heads at the ends of the branches, 2.5-3 cm. 

 high; outer bracts tapering into a stout broad-keeled spine, the inner uith narrow 

 lanceolate erose tips. Perhaps of hybrid origin. Carduus araneosus Osterh., 

 not Steud. Banks: Colo. Submoni. — Mont. Je-Au. 



3. C. scariosum Nntt, Stem slender; leaves densely white-tomentose 

 beneath, pinnatifid with short lobes; heads about 3 cm. high; bracts lanceolate 

 to lance-subulate, the outer spinulose-ciliate, the inner with lanceolate-erose tips. 

 Carduus scariostis Hook, C. Ilookcrianus Rydb. (Fl. Mont.), in part. Moun- 

 tains: Wyo. — Mont. Submont. Jl-Au. 



4. C. subniveum Rydb. Stem 6-10 dm. high, white-floccose, paniculately 

 branched above; leaves 1-1.5 cm. long, Unear in outUne, deeply pinnatifid, 

 tomentose on both sides, densely so and white beneath, more loosely so above; 

 lobes lanceolate or triangular, often toothed or lobed and armed with moderately 

 strong yellow spines; involucres 2 cm. high and nearly as broad, densely arachnoid, 

 almost floccose; outer bracts with ascending spines, 5 mm . long, the inner with 

 subulate weak tips. Valleys: w Wyo, Au. 



5. C. Kelseyi Rydb. Stem 5-20 dm. high, very leafy; leaves linear, at most 

 pinuately short-lobed, green above, somewhat tomentose or glabrate beneath; 

 heads 3-4 cm. high, erect, in a leafy spike-hke inflorescence; bracts all linear- 

 lanceolate, attenuate into short spines or slender tips. Carduus Kelseyi Rydb. 

 Mountains : Mont. Plain — SubmonL Je-Au. 



C. ButleriX Kelseyi. With the inflorescence of C. Kelseyi and the bracts of C. But- 

 leri, but slightly arachnoid-hairy, Mont. 



6. C. Hookerianum Nutt, Stem 3-6 dm. high; leaves scarcely decurrent, 

 ninnatifid, with rather distant, obloner-lanceol/ite Inh^^s anrl ^hnrt sninAa rlp.nsRlv 



tomentose beneath, sparingly floccose above; heads 2.5-3 cm. high; bracts linear- 

 subulate, attenuate into short spines, Carduus Hookerianus (Nutt.) Heller 

 Mountains: Alta. — Mont, — B.C. Jl-Au. 



