296 COMPOSITE, (composite family.) 



a(/ain pinnatijid divisions, with revolute margins; flowers cream-color. (Cir 

 sium, Tor?-, c^ Gray. ) — Sandy shores of Lakes Michigan, Huron, and Superior. 



3. C. undulatus, Gray. Wliite-ivoolli/ throughout, low and stout, leafy ; 

 leaves lanceolate-ohluu(j , partly clasping, undivided, undulate-pinnatijid, or rarelv 

 pinnately parted, moderately prickly j fTowers reddish-purple. (Cirsium, 

 Spreng.) — Islands of L. Huron to Minn., Kan., and westward. The heads 

 vary much in size. 



4. C. altissimus, Willd. Stem downy, branching (.3-10° high), /c-o/^ 

 quite to the heads ; leaces roughish-hairy above, whitened with close wool be- 

 neath, oblong-ovate to narrowltj lanceolate, undivided, sinuate-toothed, undulate- 

 pinnatijid, or twice pinnatifid, the lobes or teeth weakly prickly; heads l-|-2' 

 high; flowers chiefly purple. (Cirsium, Spreng.) — Fields and copses, ]Mass. 

 to Minn., and southward. 



Var. discolor, Gray. Stem 2-6° high; leaves nearly all deeply pinnat- 

 ifid into lanceolate or linear lobes. (Cirsium discolor, iSj)reng.) — Common; 

 N. Eng. to 111., and scjnthward. 



5. C. Virginianus, Pursh. Stem woolly, slender, simple or sparingly 

 branched (1 -3° high), the branches or long peduncles naked ; leaves lanceolate, 

 green above, whitened with close wool beneath, ciliate with prickly bristles, 

 entire or sparingly sinuate-lobed, sometimes the lower deeply sinuate-pinnatifid ; 

 heads small; outer scales scarcely prickly ; flowers purple. (Cirsium, J//c/?x.) 

 — Woods and plains, Va., Ohio, and southward. 



•(--t- Leaves green both sides, or only with loose cohwebbi/ hairs underneath ; heads 

 large ; scales scarcely prickly-pointed. 



6. C. mtlticUS, Pursh. (Swamp Thistle.) Stem tall (3-8° high), 

 angled, smoothish, panicled at the summit ; branches sparingly leafy, bearing 

 single or few rather large heads ; leaves somewhat hairy above, whitened icith 

 loose ivehby hairs })eneath when young, deeply pinnatijid, the divisions lanceolate, 

 acute, cut-lobed, prickly-pointed ; scales of the u:ebby and glutinous (.sometimes 

 glabrate) involucre closely appressed, pointless or barely mucrouate; floAvers 

 purple. (Cirsium, Michx.) — Swamps and low woods ; common. 



7. C. pumilus, Torr. (Pasture Thistle.) *S7em Zo<^• and stout (1 -2° 

 high), hairy, bearing 1 -3 very large heads (1^' broad), which are often leafy- 

 bracted at the base; leaves green, lanceolate-oblong, partly clasping, somewhat 

 hairy, pinnatijid, icith short and cut very pricki y-margined lobes ; outer scales 

 prickly-pointed, the inner very slender ; flowers purple or rarely white (fragrant, 

 2' long). (Cirsium, Spreng.) — Dry fields, N. Eng., near the coast, to Penn. 



* * * * Outer scales of the appressed involucre barely prickly-pointed ; heads 

 imperfectly dioecious, small and numerous. 



C. ARVExsis, Hoffm. (Canada Thistle.) Perennial, slender, 1 -2° high, 

 the roots extensively creeping ; leaves oblong or lanceolate, smooth, or slightly 

 woolly beneath, sinuate-pinnatifid, prickly-margined ; flowers rose-purple. 

 (Cirsium, Scop.) — Cultivated fields, pastures, and roadsides, common ; a most 

 troublesome weed, extremely difficult to eradicate. (Nat. from Eu.) 



80. CARDUUS, Tourn. Plumeless Thistle. - 



Bristles of tlie pappus naked (not plumose), merely rough or denticulate. 

 Otherwise as in Cuicus. (The ancient Latin name.) 



