GENUS 4. 



THISTLE FAMILY. 



1 6. Eupatorium perfoliatum L. 



Common Thoroughwort. Bone- 

 set. Indian Sage. Fig. 4167. 



E. perfoliatum L. Sp. PI. 838. 1753- 

 Eupatorium truncatum Muhl. ; Willd. Sp. 



PI. 3: 1751. 1804. 

 Eupatorium perfoliatum truncatum A. Gray, 



Syn. Fl. i : Part 2, 99. 1804. 



Pubescent, stout, branched above, 2-5 

 high. Leaves opposite, or rarely in 3's, 

 connate-perfoliate, or the upper, rarely 

 all, truncate and separated at the base, 

 divaricate, lanceolate, long-acuminate 

 with a slender apex, finely crenate-ser- 

 rate, rugose and pubescent beneath, 4-8' 

 long, \'-\\' wide; heads crowded, 10-16- 

 flowered, 2"-3" high ; involucre cam- 

 panulate, its bracts lanceolate, acutish, 

 in 2 or 3 series, pubescent, the outer 

 shorter ; flowers white, rarely blue. 



In wet places, Nova Scotia and New 

 Brunswick to Manitoba, Florida, Nebraska 

 and Texas. Called also ague-weed, cross- 

 wort, wild sage, thorough-wax, thorough- 

 grow, thorough-stem. July-Sept. 



E. urticae 'folium Reichard, Syst. 3 : 719. 



1780. 



E. ageratoides L. f. Suppl. 355. 1781. 

 E. boreale Greene, Rhodora 3: 83. 1901. 



Glabrous or villous and somewhat vis- 

 cid, much branched, i-4 high. Leaves 

 opposite, ovate, thin, acuminate at apex, 

 rounded, truncate or cordate at the base, 

 or abruptly narrowed into the slender 

 petiole, coarsely and usually sharply den- 

 tate-serrate, sometimes crenate, 3'-6' 

 long, i'-3' wide, 3-nerved and veiny ; 

 petioles $'-2i' long; inflorescence rather 

 loose, ample; heads io-3O-flowered ; re- 

 ceptacle flat ; involucre narrowly cam- 

 panulate, about 2" high, its bracts linear, 

 acute or acuminate, in I or 2 series, 

 equal or nearly so ; flowers bright white. 



In rich woods, New Brunswick to Flor- 

 ida, Ontario, Nebraska and Louisiana. In- 

 dian sanicle. Richweed. Stevia (Wis.). 

 White sanicle. Deerwortboneset. July-Nov. 



A plant described as Eupatorium perfoliatum 

 cuneatum Engelm.. with leaves smaller, narrowed 

 and separated at the base, from Arkansas and Mis- 

 souri, is probably a hybrid with E. serotinum. 



17. Eupatorium resinosum Torr. Resin 



Boneset. Fig. 4168. 



E. resinosum Torr. DC. Prodr. 5: 176. 1836. 



Slender, finely pubescent and resinous, 2-3 

 high, branched at the summit, the inflorescence 

 comparatively small, $'-4' broad. Leaves op- 

 posite, closely sessile, clasping, or slightly con- 

 nate-perfoliate at the base, linear-lanceolate, 

 long-acuminate, sharply serrate, 3 '-6' long, 

 3"-6" wide, roughish above, canescent beneath ; 

 heads io-15-flowered; involucre campanulate, 

 about 2" high, its bracts oblong, obtuse, in 2 

 or 3 series, the outer shorter; flowers white. 



In wet pine-barrens of New Jersey. Aug.-Sept. 



18. Eupatorium urticaefolium Reichard. 



White Snake-root.- Fig. 4169. 



