Cnictjs. composite. 405 



1. Carduus benedictus. Common Blessed Thistle. 



Linn. sp. ed. 1. p. 826 ; Muhl. cat. p. 82 ; DC. prodr. 6. p. 606 ; Torr. <^ Gr. ft. N. 

 Am. 2. p. 455. Centaurea benedicta, Linn. sp. ed. 2. p. 1296. 



Plant 1-2 feet high, branching. Leaves with spiny lobes. Heads about as large as in 

 the Common Thistle {Cirsium lanceolatum). Involucre bracteate ; the scales pinnately spiny. 



Road-sides ; rare. June. An introduced plant, but the native country uncertain. 



Subtribe II. CAKDUiNEiE, Less. Heads discoid, homogamous, many-flowered ; the flowers 

 all similar, perfect or dicecious. Scales of the involucre imbricated in several series, 

 often spinose at the apex. Corolla usually curved outwards ; the exterior often more 

 deeply cleft than the others. Anthers slightly or not at all caudate. Achenia smooth. 

 Pappus composed of slender rough or plumose bristles, which are often united into a ring 

 at the base. 



44. CIRSIUM. Tourn. ; DC. prodr. 6. p. 634:. THISTLE. 



L From the Greek, iirkos, a swelled vein ; because it was supposed to heal that disease.] 



Heads many-flowered ; the flowers perfect and similar, rarely somewhat dioecious. Scales of 

 the involucre imbricated, mostly with a prickle at the tip. Receptacle bristly. Corolla 

 5-cleft. Anthers more or less produced and lacerate at the base. Branches of the style 

 united nearly to the apex. Achenia oblong, compressed, not ribbed. Pappus of numerous 

 plumose bristles. — Herbs with sessile or decurrent leaves, which are often pinnatifid ; the 

 margin and teeth usually spiny. Heads globose or ovoid. Corolla purple, or sometimes 

 cream-colored. 



1. Cirsium lanceolatum. Scop. Common Thistle. 



Stem branching ; leaves pinnatifid, decurrent, with a spiny lobed wing, bristly above, woolly 

 underneath ; lobes and teeth tipped with spines ; involucre ovoid, arachnoid ; scales lanceolate, 

 tipped with spines , the lower ones spreading. — DC. prodr. 6. p. 636 ; Torr. <^ Gr. fl. N. 

 Am. 2. p. 456. Carduus lanceolatus, Linn. ; Engl. bot. t. 107 ; Beck, hot. p. 436 ; Darlingt. 

 fl. Cest. p. 437 ; Hooh. fl. Bor.-Am. 1. p. 302. Cnicus lanceolatus, Willd. sp. 3. p. 1666 ; 

 Pursh, fl. 2. p. 506 ; Torr. compend. p. 281 ; Bigel. fl. Bost. p. 292. 



Root biennial. Stem 2-4 feet high, stout, sulcate, winged by the decurrent leaves. Leaves 

 white underneath, armed with sharp and rigid spines. Heads about an inch and a half long. 

 Involucre contracted above ; the scales connected with a web-like tomentum. Flowers purple ; 

 the anthers yellowish. 



Fields, road-sides and waste grounds ; very common. July - October. — A vile weed ; 

 introduced from Europe, but being a biennial, it can be subdued without much labor. 



