214 COMPOSITE. (COMPOSITE FAMILY.) 



t- -i- Flowers usually rose or flesh-colored : involucral bracts closely oppressed, 

 coriaceous, commonly ivit/i 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. Pitcheri, 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 Dakota 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-Lornentose above as well as below: prickle on cusp of invo- 

 lucral bracts more or less rigid. 



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

 6 or 8 feet high, the white tomeutum mostly persistent : leaves commonly but 

 not always deeply pinnat ijid 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 

 broader glandular-viscid ridge, comparatively small and narrow, tipped icith 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. canescens, 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 laciuiate-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 



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

 leaves commonly deeply pinnatifid: heads few, only 1| inch high. Proc. 

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



