Cnicus. COMPOSITE. 403 



= Leaves pinnately parted into narrow and linear mostly entire divisions : anther-tips attenuate- 

 subulate. 



C. Pitcheri, Torr. A foot or two high, with herbage persistently white-tomentose through- 

 out: lower leaves a foot or so long, with divisions (2 to 4 inches long, 2 or 3 lines wide) 

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

 winged rhachis not wider than the divisions : heads few or solitary, 2 inches high : involucre 

 glabrate ; the bracts rather small, viscid down the back, tipped with small short prickle : 

 corollas ochroleucous. — Torr. in A. Eaton, Man. ed. 5, 180; Gray, Proc. Am. Acad. x. 42. 

 Cirsium Pitcheri, Torr. & Gray, Fl. ii. 456. — Sand-banks on the shores of the Great Lakes 

 from the head of Lake Michigan northwestward, and in Dakota, Suckleg ; first coll. by 

 Dr. Pitcher. 



= = 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 the principal involucral bracts more 

 or less rigid and pungent. 



a. Bracts of the involucre minutely scabrous-ciliolate. 

 C. Grahami, Gray. Stem 3 to 8 feet high : leaves elongated-lanceolate (larger ones a foot 

 or more long), from repand-dentate to sinuate and pinnatifid (sometimes delicately, some- 

 times strongly prickly), upper face at length glabrate and green : heads 1 J to 2 inches high : 

 involucre glabrate and greenish ; the bracts lanceolate-subulate, tipped with a short rigid 

 cusp rather than prickle, the margins at least of the principal ones minutely scabrous-ciliolate : 

 corollas crimson-red : anther-tips attenuate-subulate. — Proc. Am. Acad. xix. 57. C. undu- 

 latus, var. Grahami, Gray, Proc. Am. Acad. x. 43. Cirsium Grahami, Gray, PI. Wright, ii. 

 102 ; Hook. Bot. Mag. t. 2885. — Wet ground, Arizona, Wright, Thurber, Lemmon. 



b. Bracts of the involucre smooth and naked, or else tomentose on the margins. 



C. ochrocentrus, Gray. Resembles the next following species, usually taller, even to 6 

 or 8 feet high, the white tomentum mostly persistent : leaves commonly but not always 

 deeply pinnatifid and armed with long yellowish prickles : heads 1 or 2 inches high : princi- 

 pal 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. C. undulatus, var. ochrocentrus, Gray, Proc. Am. Acad. 

 x. 43. Cirsium ochrocentrum, Gray, PI. Fendl. 110. — Plains, &c, W. Texas to Colorado, the 

 eastern Sierra Nevada, and Arizona. (Adj. Mex.) 

 C. Undulatus, Gray. A foot or two high, persistently white-tomentose : leaves rarely pin- 

 nately parted, moderately prickly : heads commonly inch and a half high : principal bracts 

 of the involucre mostly thickened on the back by the broader glandular-viscid ridge, com- 

 paratively small and narrow, tipped with an evident spreading short prickle : corollas rose- 

 color, pale purple, or rarely white ; its lobes equalling or surpassing the throat in length : 

 anther-tips attenuate-subulate. — Proc. Am. Acad. x. 42, excl. var. ochrocentrus, & var. Gra- 

 hami. Carduus undulatus, Nutt. Gen. ii. 130. C. discolor, Hook. Fl., in part. Cirsium Dou- 

 glasii, DC. Prodr. vi. 643, excl. habitat. C. Hoolcerianum, Hook. Lond. Jour. Bot. vi. 253, not 

 Nutt. — Plains, &c, from Lake Huron and Minnesota to Saskatchewan, west to Oregon, 

 south to Kansas and New Mexico. 



Var. canescens, Gray, 1. c, is merely a form with smaller heads, sometimes not 

 over an inch high, the leaves varying from ciliately spinulose-dentate to deeply pinnatifid. — 

 Cirsium canescens & C. brevifolium, Nutt. Trans. Am. Phil. Soc. vii. 421. — Minnesota to New 

 Mexico and S. Utah. 



Var. megacephalus, Gray, 1. c. Stouter form, usually broader-leaved, with broad 

 heads 2 inches or more high. — Minnesota and Texas (where coll. by Berlandier) to Idaho. 

 C. Breweri, Gray, 1. c. Usually both very white-tomentose and tall (5 to 10 feet high) : 

 leaves mostly elongated-lanceolate, conspicuously prickly : heads paniculate, sometimes very 

 numerous, subsessile, merely inch high, or when solitary inch and a half high : bracts of the 

 globular involucre much appressed, firm-coriaceous, the tip externally bearing an oval or 

 oblong greenish viscid-glandular spot ; outer ones ovate to oblong, abruptly tipped with a 

 rather slender spreading prickle : corollas pale purple or whitish, the lobes shorter than the 

 throat : anther-tips deltoid, merely acute. — Springy soil, Sierra Nevada from Lake Tahoe 

 and Mendocino Co., California (first coll. by Anderson and Brewer), to E. Oregon, Cusick, 

 &c. Also, less white-woolly, San Juan, Monterey Co., Brewer, leading to the var. 



