1006 CARDUACEAE 



r>inp<3 of the middle bracts stout and ascending. 

 P l^per leaves i entire or with shallow lobes; involucre less than 2 cm. 



nrcmc\ vprv dcirk 49. O. CQTicsc&'ns. 



UDper leaves deeply pinnatifld; involucres about 3 cm. broad, light 

 colored! except Tthe viscid ridge. 50. C. pulchernmum. 



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

 1 Leayes^at^ast the upper ones, entire or slightly lob^ tomegtoje^bcjlj 



^S5S^1^*&f^ --ow, linear-lanceolate lo^es; .plant 



yellowish. 52 - c - Ftodmann. 



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 



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



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

 Involucres 4-7 cm. in diameter. 



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

 spicuously decurrent. 56. C. megacephalum. 

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



decurrent "" C. ochocenlrum. 



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

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



XI. ARVENSIA. 

 One species. 58 - c - arvense. 



1. C. Parryi (A. Gray) Petrak. Stem 3-10 dm. high; lower leaves petioled, 

 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 with lanceolate-erose tips, spineless. 

 Cnicus Parryi A. Gray. Carduus viridiflorus Greene. Mountains: Colo. 

 Utah N.M . Ariz. Submont. Subalp. 



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

 noid; leaves linear in outline, 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 with narrow 

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

 not Steud. Banks: Colo. Submont. Mont. Je-Au. 



3. C. scariosum Nutt. 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 scariosus Hook. C. Hookerianus 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, linear in outline, 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 

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

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

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

 Mountains: Mont. Plain Submont. 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, 

 pinnatifid, with rather distant, oblong-lanceolate lobes and short spines, densely 

 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. 



