COMPOSITAE. 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. hyssopifolium. 



Leaves lanceolate, oval or oblong, usually serrate. 



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



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

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



Leaves rounded, obtuse or truncate at the base. 



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



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. 



\ t Involucral bracts in i 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, 25 cm. long, blunt-toothed, acute or obtusish. 



20. E. aromaticum. 

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



1. 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, 1-3 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, N. Y. toKy., Minn., Br. 

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



Eupatorium maculatum amoenum (Pursh) Britton. Leaves opposite, or in 3*5 or 4*5, 

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

 base, scabrous above, finely densely pubescent and reticulate-veined beneath, 1-1.5 

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

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

 to Neb. and Colo. Type Rydberg, No. 1682, from South Fork of Dismal River, 

 Neb. 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, N. 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-LEAVED 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, crenate ; inflorescence ample, 



