402 COMPOSIT.E. Cnicus. 



-H- ++ Western species : leaves either green both sides or deciduouslj- white-woolly beneath: invo- 

 lucral bracts plane : anther-tips narrow, very acute. 



C. quercetorum, Gray. Lightly villous-arachnoid when young, soon glabrate : stem 

 stout, a foot or less high, bearing few or several thick heads: leaves mostly petiolate (the 

 larger a foot long), pinnately parted and the oblong divi.sions often 3-5-cleft, strongly or 

 weakly prickly ; involucral bracts thickisli-coriaceous, closely imbricated in numerous ranks ; 

 outer only mucronately cuspidate or with sliort prickle (outermost only about 3 lines long) ; 

 innermost obscurely scarious at tip: corollas ]jurplish or whitish, the lobes equalling or 

 longer than the throat. — Proc. Am. Acad. x. 40, & Bot. Calif, i. 418. — Dry hills, at Oak- 

 land and vicinity, California, Kellogg, Bokmdcr, &c. 



C. Drummondii, Geay, 1. c. Green and somewhat villous-pubescent, or when young 

 lightly arachnoid-woolly (at least the lower face of the leaves), either stemless and bearing 

 sessile heads in a cluster on the crown, or caulescent and efen 2 or 3 feet high, with solitary 

 or several loosely disposed heads : leaves from sinuate or almost entire to pinnately parted, 

 moderately prickly : larger heads fully 2 inches high : involucral bracts thin-coriaceous or 

 chartaceous, mostly acuminate, weak-prickly pointed or innocuous, innermost with more 

 scarious and sometimes obviously dilated and erose-fimbriate tips : corollas either white or 

 sometimes rose-purple, with lobes usually shorter than the throat. — Carduus pumihis, Hook. 

 Fl. i. 302, excl. syn. Cirsium Drummondii, Torr. & Gray, Fl. ii. 459. — From Fort Franklin, 

 near the Arctic Circle, to the Saskatchewan, along the Eocky Mountains to Colorado and 

 Utah, west to Oregon, and south along the Sierras to S. California. Polymorphous and of 

 y^vy wide range. 



Var. acaulescens, Gkay, 1. c. Sm.aller, with heads (solitary or several on the crown, 

 encircled by the radical leaves) only inch and a half long, or less, and proportionally narrow : 

 outer involucral bracts with a longer but rather weak prickle. — Cirsium acaule, var. Ameri- 

 canum. Gray, Proc. Acad. Philad. 1863, 68. — Mountains of Colorado to the Sierra Nevada 

 in S. California. 



C. f oliosus, Gray, 1. c. More woolly, usually also villous when young : stem stout, leafy 

 to the cluster of a few sessile heads, a span or two high : leaves commonlj' elongated, linear- 

 lanceolate, laciniately dentate, arachnoid-tomentose beneath : heads broad, inch ancl a half 

 high, leafy-bracteose : involucre nearly of the preceding : corollas pale or white, with lobes 

 equalling or longer than the throat. — Carduus foliosus, Hook. Fl. i. 303. Cirsium foli- 

 osiim, DC. Prodr. vi. 654. — Prairies of the northern Rocky Mountains, Drummond. Idaho, 

 Burke, Siiaiding. 



C. SCarioSUS. White with cottony tomentum, at least the lower face of the leaves : stem 

 about a foot high : leaves of lanceolate outline, mostly pinnately parted into lanceolate long- 

 prickly lobes; upper face sometimes villous, sometimes only cottony and early glabrate: 

 heads nearly of jireceiling, 2 or 3 in a sessile cluster, or solitary on short leafy branches: 

 innermost bracts of involucre commonly with more conspicuous arose or entire scarious tips : 

 corollas pale or white. — Cirsium scariosum, Xutt. Trans. Am. Phik Soc. vii. 420. — Eockv 

 Mountain plains, AVyoming and Utah, Nuitall, Ward, Paliuer, &c. Has been referred to 

 C. Americanus and (in Proc. Am. Acad. xix. 56) to C. foliosus. 



++++++ Species of Jfrxican border, with dense white tomentum, smaller and obscurely cari- 

 nate outer involucral bracts, and blunt very scarious tips to the inner: anther-tips very acute. 



C. Wheeleri, Gray. Stem slender, 2 or 3 feet high, white with close cottonv wool, as is 

 the lower face of the le:iics : these narr(3i\ly laiucolate or linear, sparingly laciniate-pinnati- 

 fid, glabrate and green above, slightly prickly : head solitary, nearly 2 inches high, naked at 

 base: outer involucral bracts firm-coriaceous, much appressed, carinate-thickened ibran the 

 middle of the back, abruptly tipped with a small weak jn-ickle; inner with conspicuous 

 scarious or scarious-edged and erose tip or a|ipcnilage; comlla crimson-purple; its lobes 

 much longer than throat. — Proc. Am. Acad. xix. 56. — P.icky Canon, south of Camp 

 Apache, Arizona, Rotlirork, in Wheeler Exped., where it was referred to C. undulatus. 



■<— -I— -I— Heads large or comparatively small - flowers usually rose or flosli-cnlnrcd : involncral 

 bracts closely appressed, coriaceous or fhickish, commonly with a glandular or viscid ridge, short 

 line, or a broader spot on the back near the summit. 



++ Oanescent, at least the lower face of the leaves white-tomentose, very rarely glabrate in age: 

 heads naked, solitary or scattered. 



