COMPOS! TAB. 92 1 



Bracts of the involucre acute or cuspidate. 



Leaves linear-lanceolate, sparingly toothed, 4-12 mm. wide. 7. E. leucolepis. 

 Leaves oblong or lanceolate, coarsely toothed, 1-4 cm. wide. 8. E. album. 

 Bracts of the involucre obtuse. 



Leaves linear, crowded, usually entire, obtuse. 9. E. hyssopi/olium. 



Leaves lanceolate, oval or oblong, usually serrate. 



Leaves linear-lanceolate, acute, dentate. 10. E.Torreyanum. 



Leaves oblong to oval, sharply serrate, obtusish or acute. 11. E. semiserratum. 

 Leaves lanceolate, sparingly dentate, long-acuminate. 12. E. altissimum. 

 j j Leaves rounded, obtuse or truncate at the base. 

 Plant glabrous; leaves lanceolate, long-acuminate. 13. E. sessilifolium. 



Plants pubescent; leaves ovate or oblong, acute or obtuse. 



Leaves ovate-oblong, to lanceolate, mostly rounded at the base, usually obtuse. 



14. E. verbenaefolium. 

 Leaves broadly ovate, crenate-dentate, mostly truncate at the base, obtusish. 



15. E. rotundifolium. 

 Leaves ovate, dentate, acute. 16. E. pubescens, 



b. Leaves clasping or connate-perfoliate at the base. 

 Leaves connate-perfoliate; involucral bracts acute. 17. E. perfoliatum. 



Leaves merely clasping ; involucral bracts obtuse. 18. E. resinosum. 



f t Involucral bracts in 1 or 2 series, all equal or nearly so. 

 Receptacle flat; flowers white. 



Leaves thin, 5-12 cm. long, sharply dentate, acuminate. 19. E. ageratoides. 



Leaves thickish, 2 5 cm. long, blunt-toothed, acute or obtusish. 



20. E. aromaticum. 

 Receptacle conic ; flowers blue or violet. 21. E. coelestinum. 



i. Eupatorium capillifolium (Lam.) Small. Dog-fennel. Hog-weed. 

 (I. F. f. 3613.) Erect, paniculately much branched, with the aspect of an Artemi- 

 sia, the stem finely pubescent, I -3 m. high. Leaves crowded, glabrous or 

 nearly so, alternate, the lower petioled, the upper sessile; heads very numerous, 

 about 3 mm. high, short-peduncled. racemose-paniculate. 3-6 flowered; bracts of 

 the involucre in about 2 series, linear, cuspidate, narrowly scarious-margined. gla- 

 brous; flowers greenish white. In fields. Va. to Fla. Also in the W. Ind. Sept. 



2. Eupatorium maculatum L. Spotted Joe-pye Weed. (I. F. f. 3614.) 

 Scabrous or pubescent, 6-18 dm. high. Stem usually striate, often rough and 

 spotted with purple; leaves thick, ovate or ovate-lanceolate, coarsely dentate, ver- 

 ticillate in 3's-5's. or the upper ones opposite; peduncles and outer scales of the in- 

 volucre pubescent; flowers pink or purple. In moist soil. X. Y. toKv., Minn.. Br. 

 Col., Kans. and X. Mex. Aug. -Sept. 



Eupatorium maculatum amoenum (Pursh) Britton. Leaves opposite, or in 3's or 4's, 

 ovate or oblong; heads smaller, fewer ; plant low. In dryer places, Va. to N. V. and Me. 



3. Eupatorium Rydbergi Britton. n. sp. Rydberg's Joe-pye Weed. Stem 

 tall, pubescent, often densely so, at least above. Leaves verticillate in 3's- 5's, 

 rather slender-petioled, lanceolate, serrate, acuminate at the apex, narrowed at the 

 ":jase. scabrous above, finely densely pubescent and reticulate-veined beneath. 1-1.; 

 dm. long. 2-3.5 cm - wide; inflorescence depressed or subpyramidal; outer bracts 

 of the cylindric involucre putrescent; flowers pink or purple. In moist soil. Iowa 



b. and Colo. Type Rydberg. Xo. 1682, from South Fork of Dismal River. 

 Xeb. July-Sept. 



4. Eupatorium purpureum L. Joe-pye or Trumpet-weed. (I. F. f. 3615.) 

 Glabrous or sparingly pubescent. 1-3 cm. high. Stem green or purple, usually 



.smooth; leaves thin, verticillate in 3's-6's. ovate, oval, or ovate-lanceolate, pet- 

 ioled. acuminate, serrate, sometimes incised, 1-3 dm. long, 3-7 cm. wide- heads 

 numerous; involucre cylindric. its bracts pink, oblong, obtuse, imbricated in 4 or 

 5 series, the outer shorter; flowers pink or purple, occasionally white. In moist 

 soil. X. B. to Man.. Fla. and Tex. Aug.-Sept. 



Eupatorium purpureum falcatum (Michx.) Britton. Leaves narrower, linear-lan- 

 ceolate, or linear-oblong, 12-30 mm. wide. With the type. 



5. Eupatorium trifoliatum L. Crenate-i.eayed Joe-pye Weed. Stem 

 tall, stout, often purple, glabrous, or very nearly so. Leaves rather firm, lanceolate 

 to oblong-lanceolate, verticillate. acute or acuminate at the apex. 1.5-2 dm. long, 

 smooth and glabrous on both sides or very nearly so, eremite ; inflorescence ample,' 



