1166 CAKDUACEAE 



the lower part of the stem, pectinate-pinnatifid or the smaller ones on the upper part of the 

 stem merely incised or repand, sessile or partly clasping : cymes disposed in a broad 

 corymb : heads numerous, densely clustered : involucres 4-5 mm. high ; bracts lanceolate 

 to linear-lanceolate or nearly linear, acuminate or acuminate-mucronate : corollas white : 

 achenes about 1 mm. long. 



In sandy soil, southern Georgia and Florida. Summer and fall. 



6. Eupatorium ser<5tinum Michx. Puberulent. Stems 1-2 m. tall, corymbosely 

 branched above : leaves opposite ; blades thinnish, lanceolate to ovate-lanceolate, 5-25 cm. 

 long, acute or acuminate, coarsely serrate, obtuse or broadly cuneate at the base : corymbs 

 ample : heads very numerous, usually crowded : involucres 3-4 mm. high, 7-15-flowered ; 

 bracts oblong-lanceolate to linear-oblong, obtuse, pubescent : corollas white : achenes 2 mm. 

 long, glabrous or nearly so. 



In low grounds, Iowa to Maryland, Florida and Texas. Late summer and fall. 



7 . Eupatorium mikanioides Chapm. Tomentulose, or glabrate in age. Stems 5-9 

 dm. tall : leaves mainly opposite ; blades fleshy, deltoid-ovate to hastate-ovate or some 

 oblong, 3-6 cm. long, obtuse or acutish, repand or crenate-dentate, broadly cuneate or sub- 

 cordate at the base : corymbs with wide-spreading branches : heads numerous : involucres 

 5-6 mm. high, 5-flowered ; bracts oblong-lanceolate to linear, acute or often cuspidate, or 

 sometimes rather blunt : corollas white : achenes about 1 mm. long, minutely glandular. 



In low sandy ground, Florida. Summer and fall. 



8. Eupatorium villoaum Sw. A branching shrub 0.5-2 m. tall, with tomentulose- 

 hoary foliage. Leaves opposite ; blades leathery, ovate to deltoid-ovate, 1.5-7 cm. long, 

 obtuse, scabrous above, tomentulose beneath, entire or repand : heads numerous : involu- 

 cres 3-4 mm. high, 8-1 5-flowered ; bracts oblong to linear-oblong, obtuse : corolla white, 

 sometimes purple-tinged: achenes 1.5-2 mm. long. 



In sandy soil, Florida. Also in the West Indies. 



9. Eupatorium ageratifolium DC. A shrub 1-3 m. tall, with spreading branches 

 and nearly glabrous foliage. Leaves opposite ; blades deltoid-ovate or ovate-lanceolate, 

 2-8 cm. long, obtuse or acutish, coarsely serrate-dentate or crenate-serrate, rounded or sub- 

 cordate at the base : heads numerous : involucres 4-5 mm. high, 10-30-flowered ; bracts 

 chaff-like, linear to linear-spatulate, obtuse or acutish : corollas usually white : achenes 

 2-3 mm. long. 



In dry soil, Texas and Mexico. Also in the West Indies. 



10. Eupatorium incarnatum Walt. Minutely pubescent. Stems sometimes reclin- 

 ing, 5-10 dm. long, often diffusely branched : leaves opposite ; blades ovate to deltoid, 

 2-6 cm. long, acute or acuminate, rather coarsely serrate, truncate or cordate at the base ; 

 petioles slender, often as long as the blades: involucres about 4 mm. high, 20-flowered ; 

 bracts few, narrowly linear, slightly ribbed when dry, acute : corollas white or pale purple : 

 achenes 2.5 mm. long, minutely pubescent. 



In woods or sandy soil, South Carolina to Florida and Texas. Also in adjacent Mexico. 



11. Eupatorium ageratoides L. f. Glabrate or puberulent. Stems 4-12 dm. tall, 

 branched : leaves opposite ; blades thin, ovate or rarely ovate-lanceolate, 4-12 cm. long, 

 acuminate, coarsely serrate, acute, often rounded or subcordate at the base : heads numer- 

 ous : involucres 3-4 mm. high ; bracts linear, acute or acutish, pubescent : corollas white, 

 with pubescent lobes : achenes 2.5 mm. long, glabrous or nearly so. 



In rich soil. New Brunswick to Ontario. Georgia, Louisiana, Nebraska and the Indian Territory. 

 Summer and fall. 



12. Eupatorium aromaticum L. Puberulent or minutely pubescent. Stems 3-10 

 dm. tall, often widely branched : leaves opposite ; blades thickish, ovate to ovate-lanceo- 

 late, 2-10 cm. long, obtuse or acute, crenate, sometimes with coarse teeth, rounded or sub- 

 cordate at the base : heads numerous : involucres 4-5 mm. high ; bracts linear or slightly 

 broadened upward, acute or fimbriate at the apex, pubescent : corollas white or nearly so : 

 achenes 2.5 mm. long, glabrous or mainly so. 



In dry woods, Massachusetts to Tennessee, Florida and Mississippi. Summer and fall. 



13. Eupatorium lecheaef olium Greene. Puberulent or finely pubescent. Stems 3-7 

 dm. tall, often slender : leaves numerous, small ones often clustered in the axils of the 

 larger ; blades narrowly linear, 1-8 cm. long, entire, revolute : heads numerous, often 

 crowded : involucres 3-4 mm. high ; bracts oblong to linear, obtuse, sometimes lacerate at 

 the apex, scarious-margined, pubescent and glandular: corollas white: achenes 2 mm. 

 long, glandular. 



In sandy soil, Florida. Summer and fall. 



14. Eupatorium hyBsopifolium L. Puberulent. Stems 3-8 dm. tall, corymbosely 

 branched above : leaves numerous, small ones often clustered in the axils of the larger ; 



