214 COMPOSITE. (COMPOSITE family.) 



h- +- Flowers usually rose or flesh-colored : involucral bracts closely oppressed, 

 coriaceous, commonly with a glandular or viscid ridge, short line or a broader 

 spot on the back near the summit : heads naked, solitary or scattered. 

 = Leaves pinnately parted into narrow and linear mostly entire divisions. 



8. C. Piteheri, Torr. A foot or two high, with herbage persistently 

 white-tomentose throughout : lower leaves a foot or so long, with divisions 

 either entire or some again pinnately parted into shorter lobes, weakly prickly- 

 tipped ; the winged rhachis not wider than the divisions : heads few or soli- 

 tary, 2 inches high : involucre glabrate ; the bracts rather small, viscid down 

 the back, tipped with small short prickle : corollas ochroleucous. — Extending 

 into the Dakotas and the northeastern limit of our range from the shores of 

 the Great Lakes. 



= = Leaves from undivided to pinnately parted, the lobes lanceolate or broader, 

 disposed to be white-tomentose above as well as below: prickle on cusp of hiro 

 lucral bracts more or less rigid. 



9. C. ochroeentrus, Gray. Resembles the next, usually taller, even to 

 6 or 8 feet high, the white tomentum mostly persistent : leaves commonly b«1 

 not always deeply pinnatifid and armed with long yellowish prickles: heads 1 or 

 2 inches high : principal bracts of the involucre broader and flatter, the viscid 

 line on the back narrow or not rarely obsolete, tipped with a prominent spreading 

 yellowish prickle: corollas purple, rarely white. — Proc. Am. Acad. xix. 57. 

 Plains, W. Texas to Colorado and Arizona. 



10. C. undulatus, Gray. A foot or two high, persistently white-tomen- 

 tose : leaves rarely pinnately parted, moderately prickly : heads commonly l£ inch 

 high : principal bracts of the involucre mostly thickened on the back by the 

 hroader glandular-viscid ridge, comparatively small and narrow, tipped with an 

 evident spreading short prickle : corollas rose-color, pale purple, or rarely white. 

 — Proc. Am. Acad. x. 42. Plains, from Oregon to the Great Lakes and 

 southward to New Mexico. 



Var. caneseens, Gray, is a form with smaller heads, sometimes not over 

 an inch high, the leaves varying from ciliately spinulose-dentate to deeply 

 pinnatifid. — New Mexico and S. Utah to Minnesota. 



= = = Leaves in the same species from undivided to pinnately parted, the lobes 

 from ovate to lanceolate, upper face soon glabrate and green : involucral bracts 

 tipped with weak prickles or sometimes hardly any. 



11. C. altissimus, Willd. Stem branching, 3 to 10 feet high : leaves in 

 the typical form ovate-oblong or narrower, sometimes with merely spinulose- 

 ciliate slightly toothed margins, sometimes laciniate-cleft or sinuate, or lower 

 ones deeply sinuate-pinnatifid, weakly prickly : heads l£ to 2 inches high: invo- 

 lucral bracts firm-coriaceous, abruptly tipped with a spreading setiform prickle, 

 the short outermost ovate or oblong : roots fascicled and not rarely tuberous- 

 thickened below the middle, in the manner of Dahlia. — East of our range, 

 but represented by 



Var. filipendulus, Gray. Smaller, 2 or 3 feet high : roots tuberiferous : 

 leaves commonly deeply pinnatifid: heads few, only Ij inch high. — Proc. 

 Am. Acad. xix. 56. Prairies and thickets, Texas and Colorado. 



