CiRSiuM. COMPOSITE. 457 



(2)? Plant 1-2 feet high. Radical leaves sinuate and less spinose. Scales 

 of the involucre at length almost glabrous, often glutinous along the midrib. 



4. C. HooJcerianum (Nutt.) : arachnoid-tomentose throughout; stem simple 

 or sparingly branched at the summit; striate; leaves lanceolate or linear, 

 sinuate-pinnatifid, with the lobes often toothed or incised, spinulose, arach- 

 noid above, canescently tomentose beneath; the cauline somewhat clasping; 

 heads (rather small) 2-5, subsessile; scales of the subglobose very woolly 

 involucre lanceolate, erect, tipped with somewhat spreading prickles ; the in- 

 nermost unarmed ; flowers apparently purple. — Null. ! in trans. Amer. phil. 

 soc. I. c. p. 418. Carduus discolor (in part). Hook. ! Ji. Bor.-Am. i. p. 302. 



Saskatchawan or Rocky Mountains? (Richardson or Drummond.) — Plant 

 12-16 inches high, slender: doubtless distinct from C. discolor; but the speci- 

 mens are not very complete. The stronger bristles of the pappus are some- 

 what more evidently clavellate or thickened at the apex than in most other 

 species. 



5. C. discolor (Spreng.) : stem striate, hirsute, with leafy somewhat spread- 

 ing branches; leaves all deeply pinnatifid, sessile, sparsely hairy and green 

 above, densely tomentose-canescent (bluish-white) beneath ; the segments 

 divaricate, mostly 2-3-lobed, lanceolate or linear-lanceolate, spinulose-ciliate, 

 and tipped with an acicular prickle ; scales of the globose involucre somewhat 

 arachnoid, appressed ; the exterior ovate and tipped with a very slender 

 spreading acicular prickle; the innermost linear-lanceolate; flowers reddish- 

 purple. — Spreno: syst. 3. p. 373; DC. prodr. 6. p. 640. Cnicus discolor, 

 Muhl! in Willd. 'spec. 3. p. 1670; Ell. sk. 2. p. 271; Bigel. fl. Bost. ed. 

 2. p. 292. Carduus discolor, Nutt. gen. 2. p. 130; Darlingt. ! fl. Cest. p. 

 437. Serratula discolor, Poir. 



Fields and along thickets, (Canada?) Northern and New England States! 

 to Illinois! Kentucky! and the upper districts of S. Carolina. .July-Sept. 

 — d) Stem .3-6 feet high ; the rather slender branches leafy to the summit, 

 and terminated by heads an inch or more in diameter. Leaves of the 

 branchlets quite small ; the lower cauline 6-12 inches long (the white persis- 

 tent tomentum very closely appressed) ; the segments mostly long and narrow, 

 often falcate. 



6. C. altissimum (Spreng.) : stem tall, pubescent or somewhat woolly, 

 branching; the branches leafy to the summit; leaves roughish-pubescent 

 above, densely tomentose-canescent beneath, spinulose-ciliate ; the radical 

 petioled, pinnatifid ; the cauline sessile, oblong-lanceolate, either undivided, 

 sinuate-toothed, or sinuate-pinnatifid; the lobes or teeth spinescent; heads 

 (rather large) bracteate ; scales of the globose-ovoid involucre arachnoid 

 when young, appressed ; the exterior ovate-lanceolate, tipped with a spread- 

 ing acicular prickle ; the innermost narrow, with scarious acuminate tips ; 

 flowers mostly purple. — DC. ! pwdr. 6. p. 640, S^not. 8. pi. rar. Genev. p. 6. 

 C. altissimum, laciniato folio, &c.. Dill. Elth. 1. p. 81, t. 69. C. diversi- 

 foHum, DC. ! prodr. I. c. p. 649. Carduus altissimus, Linn. spec. 2. p. 824 ; 

 Nutt. gen. 2. p. 129; Darlingt.fi. Cest. p. 439. Cnicus altissimus, Willd. 

 spec. 3. p. 1671 ; Ell. sk. 2. p. 268. 



Fields and thickets, Pennsylvania! and Ohio! to Western Missouri! 

 Louisiana! Alabama! Carolina! &c. Aug.-Sept.— If ? Stem 3-10 feet 

 high. Leaves quite variable in outline ; sometimes the radical undivided : 

 when the cauline are pinnatifid, the lobes are usually few and short, oblong 

 or triangular. Scales of the involucre with a livid line or spot near the apex, 

 which is often somewhat glutinous. Heads about an inch in diameter. 



7. C. Virginianum (Michx.) : stem slender, simple or loosely branched 

 above, arachnoid ; the branches or peduncles nearly naked ; leaves sessile, 



VOL. 11. — 58 



