296 COMPOSITE. (COMPOSITE FAMILY.) 



again pinnatijid divisions, with revolute margins; flowers cream-color. (Cir 

 slum, Torr. $ Gray.) Sandy shores of Lakes Michigan, Huron, and Superior. 



3. C. undulatus, Gray. White-u-ool/t/ throughout, low and stout, leafy ; 

 leaves lanceolate-o'i/ong, partly clasping, undivided, undulate-pinnattjid, or rarelv 

 piunately parted, moderately prickly; flowers 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, brandling (3-10 high), leaf// 

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

 neath, oblong-ovate to narrowly lanceolate, undivided, sinuate-toothed, undidate- 

 pinnatijid, or twice pinnatijid, the lobes or teeth weakly prickly; heads l-J-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, Spreng.) Common; 

 N. Eng. to 111., and southward. 



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

 branched (1 -3 high), the braiic/iis or long peduncles naked; leaves lanceolate, 

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

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

 heads small ; outer scales scarcely prickly ; flowers purple. (Cirsium, 3[ichx.) 

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



<-- Leaves green both sides, or only with loose cobicebbi/ hairs underneath ; heads 

 large ; scales scarcely prickly-pointed. 



6. C. muticus, 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 with 

 loose irebbi/ hairs beneath when young, deeply pinnatijid, the divisions lanceolate, 

 acute, cut-lobed, prickly-pointed; scales of the irebbi/ and glutinous (sometimes 

 glabrate) involucre closely appressed, pointless or barely mucronate; flowers 

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



7. C. pumilus, Torr. (PASTURE THISTLE.) Stem low and stout (1 -2 

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

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

 hairt/, pinnatijid, with short and cut vert/ prickly-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 En.) 



80. CARDUUS, Tourn. PLDMELESS THISTLE. 



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

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



