384 COMPOSITE carduus 



innocuous with more ecarious and sometimes obviously dilated and erose- 

 fimbriate tips : corollas white to rose-purple, with lobes usually shorter 

 than the throat. From the Arctic sea-shore to California and the Rocky 

 Mountains. 



C. foliosns Hook. Fl. i, 303. Stems erect, robust, striate, somewhat 

 woolly, leafy to the cluster of a few sessile heads, 12-18 inches high : 

 leaves commonly elongated, linear-lanceolate, laciniately dentate, with 

 rather rigid prickles, arachnoid-tomentose beneath : heads broad, inch and 

 a half high leafy-bracteose : involucral bracts thin-coriaceous: corollas pale 

 or white, with lobes equalling or longer than the throat. Idaho to the 

 Rocky Mountains. 



■*-•*-•*- Heads large or comparatively small: involucral bracts 

 closely appressed, coriaceous or thickish, commonly with a glandular 

 or viscid ridge, short line, or broad spot on the back near the summit. 



€. undulatns Nutt. Gen. ii, 130. Persistently white-tomentose, 1-4 

 feet high : leaves lanceolate or oblong-lanceolate, sessile or decurrent, or 

 the lowest petioled, undulate, lobed or pinnatifid the lobes dentate, trian- 

 gular, often very prickly : heads about 2 inches broad, nearly as high, soli- 

 tary at the ends of the branches : principal bracts of the involucre mostly 

 thickened on the back by the broad glandular- viscid ridge, comparatively 

 narrow, tipped with short spreading prickles : corollas rose color or pale 

 purple to white, with lobes equalling or longer than their throats. Dry 

 prairies, Brit. Columbia to Oregon, New Mexico and Lake Huron. 



Var. megacepkalus Greene 1. c. Stouter, usually broader-leaved; 

 with broad heads 2 inches or more high. Idaho to Minnesota and Texas. 



C. Brewcri Greene 1. c. 363. Usually white-tomentose, 4-10 feet high : 

 leaves mostly elongated lanceolate, conspicuously prickly : heads panicu- 

 late, sometimes very numerous, subsessile, an inch or more high : bracts 

 of the globular involucre much appressed, firm coriaceous, with an ohlong 

 or oval greenisli viscid-glandular spot near the tip; outer ones ovate to 

 oblong, abruptly tipped with a rather slender spreading prickle: corollas 

 pale purple or whitish, the lobes shorter than the throat. Moist places, 

 southern and eastern Oregon to California and Nevada. 



90 SILYBUM Gsertn.Fr. ii, 308. (Milk Thistle) 



Annual or biennial herbs with large alternate clasping sinuate- 

 lobed or pinnatifid white-blotched leaves, and large discoid heads 

 of purple tubular flowers, solitary at the ends of the branches, 

 involucre broad, subglobose ; its bracts rigid, imbricated in many 

 series, the lower ones fimbriate-spinulose at the broad triangular 

 summit, the middle ones similar but armed with stout spreading 

 or recurved spines ; the inner ones lanceolate. Receptacle flat, 

 densely bristly. Corollas with slender tube and deeply 5-c'eft 

 limb. Filaments united below, glabrous. Anthers sagittats at 

 base. Style nearly entire. Achenes obovate-oblong, compressed, 

 glabrous, surmounted* by a papillose ring. Pappus-bristles in 

 several series, flattish, barbellate or scabrous. 



S. Mabiandm Gsertn. 1. c. 378. Stout, 2-4 feet high, little branched, 

 glabrate or glabrous: leaves oblong-lanceolate, prickly, sinuate or pinnati- 

 fid, the lower often a foot long, green blotched with white along the veins : 

 heads about 2% inches broad : corollas rose-purple, deeply cleft : pappus- 

 bristles white, barbellate. Waste places and road-sides, Brit. Columbia to 

 California. Naturalized from Europe. 



