276 COMPOSITE. Silpiiium. 



hispid-scabnms, especially beneath ; die radical ones very large and on long 

 petioles; tlie cauline very few, oblong; heads (rather large) in a loose ir- 

 regular panicle ; scales of the involucre glabrous, the exterior orbicular, the 

 others obovate or oval, obtuse ; rays numerous ; achenia obovate, very nar- 

 rowly winged, emarginate-2-toothed. — Linn. su2i2^L p. 383 ; Jacq. hort. 

 Vin'doh. lU. 43; G^rfji. fr. 1. 171 ,- Aif.! Kew. {eel. 1) 3. ji. 267; Michx. ! 

 fl. 2. p. 145 ; Schkuhr, liandh. t. 2G2 ; Pursh, I. c. ; DC! I. c. ; Hook. hot. 

 mas;- t. 3525 ,- not of Ull. 



Prairies and dry open woods, Michigan I and throughout the Western 

 States! to Louisiana! and the western part of Georgia! July-Sept. — Stem 

 4-9 feet highj leafless except near the base, exuding a copious resinous juice. 

 Radical leaves often more than 2 feet long, resembling those of the Burr-docJc, 

 but more rigid (the plant is sometimes called Prairie Burr-dock) ; the short 

 hispid liairs arising from a broad papillose base, in which a resinous matter 

 is frequently deposited, and the cuticle desquamates, so that the leaf appears 

 thickly sprinkled with white scurfy dots, particularly the lower surface. " 

 Heads about an inch in diameter, excluding the rays, which are an inch or 

 more long. The narrow wings of the achenia either entirely confluent with 

 the teeth of the achenia, which tlien appears rather deeply emarginate ; or the 

 wings are somewhat contracted at the summit, which is then more obtusely 

 toothed, and less deeply emarginate. 



3. .S. jyinnafifidum (Ell.) : glabrous, except the petioles and lower surface 

 of the leaves, wliicii are more or less hirsute and scabrous; leaves large, ob- 

 long, varying from pinnately incised to deeply pinnatifid ; the radical on 

 long petioles, sliglifly cordate, the cauline few and cuneiform at the base ; 

 exterior scales of the involucre orbicular, the inner broadly oval ; rays nu- 

 merous ; achenia oval-obovate, very narrowly winged, obtusely emarginate 

 and slightly 2-toothed. — Ell. ! sk. 2. p. 462 ; DC.prodr. b. JJ. 512. 



Prairies, western part of Georgia and Alabama, Elliott ! Mr. Buckley ! 

 Ohio, J)r. Riddcll! Mr. Sullivant! Aug.-Sept. — Plant with the habit of 

 the preceding, and with equally large leaves and heads, rays an inch and a 

 lialflong. Achenia with 2 very short and rounded callous teeth. — x\s this 

 plant bears in its foliage the same relation to the true S. terebinthinaceuni 

 that S. compositum of Michaux does to the S. terebiuthinaceum of Elliott, 

 and presents no other sulFiciently marked characters, it may not improbably 

 prove to be a variety of the preceding. 



4. S. com/positum (Michx.) : glabrous ; stem virgate, nearly naked, glau- 

 cous ; radical leaves broadly ovate, cordate, or reuiform-cordate, on long pe- 

 tioles, angulate-toothed, sinuate-toothed, or deeply and irregularly pinnatifld, 

 often ternately divided, the petiolulate divisions sinuate-pinnatifid or toothed, 

 glabrous above, sparsely pubescent beneath when young, the margins mi- 

 nutely ciliate and scabrous ; heads (small) numerous, in a spreading cymose- 

 corymbosc panicle ; scales of the involucre glabrous, obtuse, the exterior oval, 

 the others obovate or spatulate ; rays 9-12 ; achenia obovate-orbicular, rather 

 broadly v/inged, deeply and narrowly eraarginated; the wing confluent with 

 the acute or subulate teeth. 



a. Mlchauxii : leaves deeply sinuate-pinnatifid, or sometimes ternately 

 divided, the divisions (3-9) sinuate-lobed or toothed. — S. compositum, 

 Michx. ! fl. 2. p. 145 ; Willd. spec. 3. p. 2331 ,; Pursh, fl. 2. 2^- 5~7 ; Ell. 

 sk. 2. p. 462,- DC! 2^rodr. 5. p. 512. S. laciniatum, Walt. Car. p. 217, 

 not of Linn. S. sinuatum, Herh. Banks.! S. nudicaule, Curtis! cat. 

 Wilmingt. 2^1- in Bost. jour. nat. hist. (1835) 1. p. 127. S. terebinthaceum 

 /3. sinuatum, Curtis ! mss. 



/3. reniforme : leaves (larger) roundish or reniform-cordate, sinuate-toothed 

 or angulate, or slightly lobed. — S. datum, Pursh, I. c. (ex. descr.) S. tere- 

 biuthinaceum, EU. sk. 2. 2'- 463, not of Linn. S. reniforme, Raf. med. fl.. 

 2. 2>- 283 ; Nutt. ! in trans. Amer. phil. soc. I. c. j?. 342. 



