458 COMPOSlTyE. Cirsium. 



lanceolate or linear-lanceolate, green and glabrous above (or sparingly pubes- 

 cent when young), tomenlose-canescent beneath, with spinulose-ciHaie (at 

 length revolute) margins, either entire, repandly spinulose-toothed, or 

 sparingly sinuate-lobed ; the radical petioled, often sinuate-pinnatifid ; heads 

 small,°not bracteate ; scales of the subglobose involucre somewhat arachnoid 

 when young, with a glutinous keel near the apex, appressed ; the exterior 

 ovate and lanceolate, tipped with a short cuspidate spreading prickle; the 

 innermost attenuate, unarmed; flowers purple. — Michx.! fi. 2. p. 90 ; DC. 

 prodr. 6. p. 653. Carduus Virginianus, Linn. ; Jacq. obs. 4. t. 99 ; JSutt..' 

 I. c. Cnicus Virginianus, Pursh,fl.. 2. p. 506 ; Ell. sk. 2. p. 270. 



l3. lower cauliiie and radical leaves all deeply sinuate-pinnatifid, with the 

 segments often 2-3-lobed ; the upper very small, linear, entire. 



y. stem more leafy, much branched and paniculate above; leaves mostly 

 pinnatifid and more spinescent. — Cnicus arvensis. Hook.! in compan. to hot. 

 mag. 1. p. 48. 



6.1 stem stouter, sparingly branched, leafy; leaves all deeply pinnatifid, 

 with the lobes spinescent; heads larger (roots often tuberiferous). — C filipea- 

 dulum, Engelin. ! mss. 



Pine woods, &c., Virginia to Georgia ! Alabama ! and Kentucky ! 

 jS. & y. Louisiana ! Ohio T &c. 6. Tex'as, Drummond ! Dr. Lindheimer! 

 April-Sept.— 24 or (|) ?— Stem 2-3 feet high. Heads about half an inch in 

 diameter, smaller than in any of our species except C. arvense. In var. 6. ? 

 which is not unlikely either a distinct species or a variety of C. altissimum, 

 the heads are nearly as large as in the latter. 



* » Scales of the involucre appressed, regularly imbricated in several unequal series, 

 unarmed, vmcronate, or the exterior cuspidate with a short erect prickle : heads naked, 

 or merely bracteate at the base. 



8. C. muticum (Michx.) : stem tall, striate-angled, somewhat glabrous, 

 paniculate at the summit ; the branches sparingly leafy, bearing 1-few 

 heads ; leaves sessile, sparsely hairy above, arachnoid-tomentose beneath, 

 when old often nearly glabrous, deeply pinnatifid ; the segments lanceolate, 

 sparingly lobed or incised, acute, pointed with spines, the margins ciliate- 

 spinulose ; scales of the subglobose involucre villous-arachnoid and somewhat 

 viscid, appressed, unarmed; the exterior ovate or ovate-lanceolate, often mu- 

 cronate ; the innermost elongated, linear-lanceolate, acute ; flowers purple. 



Michx. ! fi. 2. p. 89 ; DC ! prodr. G. p. 652. C. Bigelowii, DC. I. c. 



Carduus muticus, Nutt. ; Hook. fi.. Bor.-Am. 1. p. 302 ; Darlingt. ! fi. 

 Cest. p. 438. Cnicus muiicus, Pursh, I. c. ; Ell. sk. 2. p. 268. C. gluti- 

 nosus, Bigel. ! fi. Bast. ed. 2. p. 291, not of Lam. 



^. leaves often glabrous or nearly so, more rigid and spinescent; the seg- 

 ments linear-lanceolate. — Carduus glaber, ISutt. gen. 2. p. 129. Cnicus 

 glaber. Ell. sk. 2. p. 270 ? Cirsium Nuttallii, DC. prodr. 6. p. 651 ? 



Low shaded grounds and swamps, Canada ! and Saskatchawan ! to 

 Louisiana! and Texas ! the var. (3. (which is not very distinct) growing 

 in more exposed places, and prevailing in the Southern and Southwestern 

 Stales! Aug.-Sept.— If or (|) ? Stem 3-8 feet high. Margins of the 

 leaves strongTv ciliate-spinulose when the jilant grows in exposed places ; the 

 ciliate prickles weak and bristly when in deep shade. Heads half an inch 

 to an inch in diameter ; the dense cobwebby hairs which clothe the involucre 

 partly disappearing with age. Marginal flowers sometimes with the stamens 

 sterile, and the pappus sparingly or not at all plumose. 



9. C. Lecontei : stem simple, slender, angled, naked at the summit and 

 terminated by a single (rather large) head ; leaves linear-lanceolate, acute, 

 spinulose-ciliolate, sparingly toothed, the teeth spinose, glabrous above, 



