212 COMPOSITE. (COMPOSITE FAMILY.) 



71. C NIC US, 1 Tourn., L., partly. PLUMED THISTLE. 



Stout herbs; with sessile leaves, commonly with prickly teeth and tips, 

 and large or middle-sized heads : the flowers red or purple, rarely white or 

 yellowish. Cirsium, DC. 



* Bracts of the ovoid or hemispherical involucre appressed-imbricated and the 



outer successively shorter, all with loose and dilated fimbriate or lacerate white- 

 scarious tips. 



1. C. AmericaiTllS, Gray. A foot or two high, branching above: 

 branches bearing solitary or scattered naked heads : leaves white-tomentose 

 beneath, lanceolate or broader, sinuately piunatifid, or some merely dentate, 

 others pinnately parted, weakly prickly : heads erect, an inch high : principal 

 bracts of the involucre naked-edged or merely fimbriate-ciliate below, and the 

 dilated scarious apex as broad as long, fimbriate-lacerate, tipped with a barely 

 exserted cusp ; innermost with lanceolate nearly entire scarious tips : flow- 

 ers ochroleucous : stronger pappus-bristles dilated-clavellate at tip. Proc. 

 Am. Acad. xix. 56. Lower mountains of Colorado and New Mexico to 

 California. 



* * Bracts of the involucre mostly loose, not appressed-imbricated nor rigid, taper- 



ing gradually from a narrow base to a slender-prickly or muticous apex ; outer 

 not very much shorter than the inner, wholly destitute of dorsal glandular ridge 

 or spot : pappus-bristles not clavellate-tipped. 



2. C. Pavryi, Gray. Green, lightly arachnoid and villous when young, 

 2 feet or so high : leaves lanceolate, sinuate-dentate., not decurrent, moderately 

 prickly: heads several and spicately glomerate or more racemosely panicu- 

 late, more or less bracteose-leafy at base : accessory and outer proper bracts or 

 some of them pectinately Jimbriate-ciliate down the sides, innermost ivith more or 

 less dilated or margined mostly lacerate-fimbriate tips : corollas pale yellow ; 

 the lobes longer than the throat : pappus of fine soft bristles, none of them 

 obviously clavellate. Proc. Am. Acad. x. 47. Mountains of Colorado and 

 Utah. 



3. C. eriocephalllS, Gray. Loosely arachnoid-woolly and partly gla- 

 brate, very leafy : leaves pinnalifid into very numerous and crowded and numer- 

 ously prickly short lobes, the base decurrent on the stern into prickly wings : heads 

 several, sessile, and crowded in a leaf-subtended at first nodding glomerule ; 

 the subtending leaves and the involucral bracts densely long-woolly, all very slender- 

 prickly : corollas light yellow or yellowish. Alpine region of the Rocky 

 mountains of Colorado. 



* * Bracts of the involucre moderately unequal or the lower not rarely about 



equalling the upper, more rigid and imbricated at base, but most of them with 



1 The naturalized genus Arctium, " Burdock," may be known by the hooked tips of its 

 involucral bracts forming a bur, otherwise unarmed ; large mostly cordate leaves ; and 

 rather small heads of pink or purplish flowers. The species is 



A. Lappa, L., and is 3 to 5 feet high, with cymose heads, leaves green and glabrous above 

 but whitish with cottony down beneath, and in the larger forms with the bur an inch or 

 more in diameter, its bracts all spreading and glabrous. 



