THISTLE FAMILY 1007 



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7. C. scopulorum (Greene) Cockerell. Stem 3-6 dm, high, very leafy; 



leaves more or less decurrent, pinnatifid, with numerous triangular or ovate 



lobes, glabrate and green above, more or less tomentose beneath; heads 3-4 cm. 



high; bracts hnear-subulate, attenuate into long yellowish spines. Cnicus erio- 



cephalus A. Gray. Cirsiujn eriocephalum A. Gray, Carduus Hookerianus (Fl. 



Colo.) in part. Carduus scopulorum Greene. Mountains; Colo. — Wyo. Mont 

 — Subalp, 



S. C, polyphyllum Rydb. Stem stout, 3-8 dm. high, very leafy; leaves 

 1-2 dm. long, deeply pinnatifid, with lanceolate divisions ending in yellow spread- 

 ing spines; heads hemispheric, about 3 cm. high and broad; bracts linear-subulate, 

 the outer with rather long yellow spines often 1 cm. long. Carduus polyphyllum 

 Rydb. Mountains: Mont. — ^Alta. Subalp, Jl-Au. 



9. C. edule Nutt. Stem 1-2 m. high, sparingly arachnoid, moderately 

 leafy; leaves pinnately cleft; divisions again 2-3-lobed, with broadly triangular 

 lobes, sparingly arachnoid and green above, grayish floccose beneath, weakly 

 spiny; heads solitary or 2 or 3 together, leafy-bracted; bracts conspicuously 

 arachnoid, gradually tapering into short spines. Cnicus edidis A. Gray. Low 

 ground: B.C. — Mont. — Calif, Son, — SuhmonL Je-Au. 



10. C. Macounii (Greene) Rydb. Stem 3-10 dm. high; leaves pinnatifid, 

 with broadly ovate lobes, toothed and with weak spines, arachnoid-hairy and 

 somewhat tomentose beneath; involucres 2.5-3 cm. high; bracts hnear-subulate, 

 the outer with weak dark brown or purphsh spines, the inner almost innocuous. 

 Carduus Macounii Greene. Valleys: Alta. — Mont. — Wash. — B.C. Submont. — 

 Mont. 



11. C. Tweedjri Rydb. Stem stout, 3-5 dm. high, in age glabrate; leaves 

 not decurrent, shining, somewhat glaucous, pinnatifid, with rounded-ovate lobes, 

 with short yellow spines; heads about 3 cm. high, somewhat leaf}'-bracted; bracts 

 with short yellowish spines 5-8 mm. long. Carduus Tweedyi Rydb. Moun- 

 tains: Mont. — n Wyo, Jl-Au. 



12. C. hes|)erium (Eastw.) Rydb. Stem stout, leafy, almost glabrous, 3-4 

 dm. high; leaves 10-15 cm. long, pinnatifid with numerous rounded lobes, with 

 yellow spines up to 5 mm. long, glabrate above, tomentose beneath; heads 

 terminal, sessile in an erect cluster; involucres 2 cm. high; bracts with broad 

 yellowish bases, tapering into long brownish spines; flowers light purple or pink. 

 Cnicus hesperius Eastw. Carduus hesperius (Eastw.) Heller. Mountains above 

 timberline: Colo. Alp. — Subalp, Au. 



13. C. lanceolatum (L.) Hill. Stem 1-1.5 m. high, more or less villous 

 when young; leaves deeply pinnatifid, with lanceolate lobes and long stout spines, 

 grayish tomentose or glabrate beneath; heads scattered at the ends of the branches, 

 4-5 cm. high; bracts lanceolate, attenuate, with long yellowish spines; flowers 

 rose-purple. Carduus lanceolatus L. Waste places and roadsides: N.S. — Ga.— 

 Calif. — B.C.; nat. from Eu, Jl-S. 



14. C. neomexicanum A. Gra^. Stem 6-12 dm. high, white-tomentose ; 

 leaves lanceolate or oblong-linear, smuately pinnatifid, with short ovate or tri- 

 angular lobes ending in weak yellow spines, tomentose on both sides; heads soli- 

 tary or few, hemispheric; bracts linear-subulate, ending in rather stout yellow 

 spines; corolla pink or white. Carduus neomexicanus Greene. Plains: N.M. — 

 Colo. — ^Ariz. Son. Ap-Jl. 



15. C. humboldtense Rydb. Stem strict, rather slender, 5-10 dm. high, 

 sparsely arachnoid-pubescent; leaves loosely floccose, pinnatifid, with short tri- 

 angular lobes and rather short spines; heads few or solitary; bracts linear-lanceo- 

 late, without a dorsal glutinous ridge, in age more or less spreading, gradually 

 tapering into yellow spines, 3-6 mm. long; corollas white. Carduus nevadensis 

 Greene. Mountains and hills: Nev.— sw Utah— nw Ariz. Son, My-Je. 



16. C. Centaureae (Rydb.) K. Schum. Stem rather slender, 6-10 dm. high; 

 leaves deeply pinnatifid to near the midrib, above fight green, beneath more or 

 less permanently grayish tomentose; lobes lanceolate or triangular, with weak 

 spines, the upper sessile and clasping, lanceolate and undivided; heads 2-2.5 cm. 



