Genus 4.] 



THISTLE FAMILY. 



309 



7. Eupatorium hyssopifolium L,. 



Hyssop-leaved Tlioroughwort. 

 (Fig. 3619.) 



Eupatorium hyssopifolium L- Sp. PI. S36. 1753. 

 E. linearijohum Walt. Fl. Car. 199, 17S8. 



Roughish-puberulent, densely corymbosely 

 branched above, bushy, i°-2° high. Leaves 

 linear, opposite, and fascicled in the axils of the 

 stem, or on short axillary branches, entire or 

 very nearly so, ]'z'-2' long, \"-2" wide, firm, 

 obtuse at the apex, narrowed at the base; in- 

 florescence densely cymose-paniculate; heads 

 2,"-\" long, about 5-flovvered; involucre cani- 

 panulate, its bracts linear or linear-oblong, ob- 

 tuse or truncate, sometimes apiculate, puberu- 

 lent, imbricated in about 3 series, the outer 

 shorter; flowers white. 



In dry fields, Massachusetts to Florida and 

 Texas. Called also Justice-weed. Leaf-margins 

 usually revolute. .\ug.-Sept. X plant from the 

 coast of Maryland with very narrow leaves, closely 

 approaches Eupatorium teclieaefolium Greene, 

 from Florida. 



8. Eupatorium Torreyanum Short. 



Torrey's Thoroughwort. (Fig. 3620.) 



Eupatorium Torreyanum Short, 2nd Suppl. Cat. 



PI. Ky. 5. 1836. 

 Eupatorium livssopifoltnm var. laciniatum A. 



Gray, Syn. Fl. i: Part 2, q8. 18S4. 



Rootstock tuberous-thickeued; stem usually 

 densely puberulent, mostly branched above, 

 i^^°-3° high. Leaves opposite, or sometimes 

 in 3's, commonly with short leafy branches in 

 their axils, often drooping, lanceolate, acute 

 at the apex, narrowed at the base, sessile, i'-. 

 3' long, 2"-6" wide, usually distinctly 3- 

 nerved, distantly serrate, the upper and those 

 of the branches much smaller, linear, entire; 

 inflorescence mostly loose; heads about 3" 

 high, generally 5-flowered; bracts of the cam- 

 panulate involucre linear-oblong, obtuse, 

 pubescent, or puberulent, imbricated in about 

 3 series, the outer shorter; flowers white. 



In dry soil, Pennsylvania to North Carolina, 

 Kentucky, Florida and Texas. July-Sept. 



^1 



9. Eupatorium semiserratum DC. 



Small-flowered Thoroughwort. 

 (Fig. 3621.) 



EupatoriuiH ainbiguum Hook. Comp. Bot. 



Mag. 1:96. In part. 1835. 

 E. semiserratum DC. Prodr. 5: 177. 1836. 



Pubescent or puberulent, loosely branched 

 above, 2°-3° high. Leaves rather thin, short- 

 petioled, oblong-lanceolate to spatulate, acute 

 orobtusish at the apex, narrowed at the base, 

 sharply serrate, at least above the middle, 2'- 

 4' long, 5"-i2" wide, 3-nerved, usually with 

 short branches in their axils; inflorescence 

 cymose-paniculate; heads 2"-y high, about 

 5-flowered; involucre campanulate, its bracts 

 linear-oblong, obtuse.canescent.inibricated in 

 2 or 3 series, the outer shorter; flowers white. 



In dry soil, Virginia to Florida, Texas and 

 Arkansas. ."Vug.-Sept. 



