406 COMPOSITE. CIRS10M 



2. CiRsruM DISCOLOR, Spreng. Two-colored Thistk. 



Stem slender, hairy, with spreading branches ; leaves deeply pinnatifid, sessile, slightly 

 hairy and green above, densely woolly and whitish underneath ; the segments lanceolate, 

 divaricate and mostly 2-lobed, tipped with a divaricate prickle ; involucre ovoid-globose ; the 

 scales appressed, ovate-lanceolate, tipped with a slender spreading prickle. — Spreng. syst. 3. 

 p. 373 ; DC. prodr. 6. p. 640 ; Torr. ^ Gr. fl. N. Am. 2. p. 457. Cnicus discolor, Muhl. 

 in Willd. sp. 3. p. 1670 ; Ell. sk. 2. p. 271 ; Bigel. Jl. Bost. p. 292. Carduus discolor, 

 Nutt. gen. 2. p. 130 ; Beck, hot. p. 173 ; Darlingt. fi. Cest. p. 437. 



Root biennial. Stem 2-6 feet high, with slender leafy branches, deeply striate, sparsely 

 clothed with crisped vesicular hairs. Leaves 4-8 inches or more in length, with scattered 

 hairs above like those of the stem ; the under surface woolly with a soft closely pressed 

 bluish-white tomentum. Heads about an inch and a half long ; the scales gradually longer 

 and narrower from the base upward , the innermost destitute of spiny tips. Flowers rather 

 pale purple. 



Old fields, thickets, etc. ; rare in the interior of the State, but not uncommon near New- 

 York. August - September. 



3. CiRsiUM MUTicuM, MicJix. Awuless Swamp Thistle. 



Stem tall and rather slender, smoothish, sparingly and paniculately branched above ; leaves 

 sessile, deeply pinnatifid, arachnoid-woolly (or sometimes nearly smooth) underneath ; the 

 segments lanceolate, spreading, with few incised spiny teeth ; involucre globose-ovate ; the 

 scales glutinous, connected by a white cobweb-like wool, closely appressed, unarmed, or the 

 exterior somewhat mucronate. — Michx. Jl. 2. p. 89; DC. prodr. 6. p. 652; Torr. <^ Gr. 

 Jl. N. Am. 2. p. 458. C. Bigelovii, DC. I. c. Carduus muticus, Nutt. gen. 2. p. 129 ; 

 Hook.Jl. Bor.-Am. 2. p. 302 ; Beck, hot. p. 172 ; Darlingt. Jl. Cest. p. 438. Cnicus muticus, 

 Pursh, Jl. 2. p. 506 ; Ell. sk. 2. p. 268. C. glutinosus, Bigel. Jl. Bost. p. 291. 



Perennial ? Stem 3-6 feet high, striate and angular, more or less pubescent. Leaves 

 4-8 inches long, clasping ; in more exposed situations usually grayish white underneath, 

 with rather remote and spiny segments ; but in deep and shady swamps, with weaker prickles, 

 little or no tomentum underneath, and wider and more approximate lobes. Heads densely 

 clothed (except the upper part) with white cobweb-like hairs. Flowers purple. 



Swamps and moist thickets. Southern part of the State. Rare in the western counties 

 {Dr. Knieskern). August - September. 



4. CiRsiuM PUMiLUM, Spreng. Pasture Thistle. 



Stem usually low, stout, hairy, bearing 1-3 very large heads ; leaves lanceolate-oblong, 

 partly clasping, green on both sides, pinnatifid ; the segments irregularly incised or lobed, and 

 very spinose ; involucre ovoid-globose ; the scales appressed, acuminate, tipped with a short 



