CAEDUACEAE 1165 



stem pubescent : involucres 4 mm. high. 

 Involucres 5-6 mm. high, over 2 mm. thick. 

 Lower leaf-blades decidedly broadest above the middle. 

 Involucres about 5 mm. high : cauline leaves with entire 



blades. 

 Involucres about 7 mm. high : cauline leaves with toothed 

 blades. 

 Bracts of the involucre acute, acuminate or mucronate. 



Leaf-blades linear or of a linear type : involucre 6-7 mm. high. 

 Inner bracts of the involucre merely acute : leaf-blades 1- 



ribbed. 

 Inner bracts of the involucre awn-tipped : leaf-blades 3- 

 ribbed. 

 Leaf-blades of an oblong or lanceolate type : involucres 8-10 

 mm. high. 

 Outer bracts of the involucre subulate-lanceolate, acuminate, 



inner bracts linear, not petaloid, acuminate. 

 Outer bracts of the involucre linear, acute : inner bracts 

 spatulate, petaloid, mucronate. 

 Base of the leaf-blade broady rounded, cordate, truncate or broadly 

 cuneate. 

 Leaf-blades crenate, crenate-serrate or crenate-dentate. 



Branches of the inflorescence alternate : leaf-blades coarsely 



few-toothed. 27. E. verbenaefolium. 



Branches of the inflorescence opposite : leaf-blades more finely 

 and evenly toothed. 

 Leaf-blades about as broad as long, truncate or subcordate 



at the base. 28. E. rotundifoHum. 



Leaf-blades manifestly longer than broad, rounded or 

 broadly cuneate at the base. 

 Involucres over 4 mm. high : leaf-blades rounded at the 



base. 

 Involucres less than 4 mm. high : leaf-blades broadly cu- 

 neate at the base. 

 Leaf-blades sharply serrate. 

 B. Leaf-blades connate-perfoliate or connate-clasping. 

 Leaf-blades connate-clasping. 



Involucre cylindric, about 5 mm. high; bracts mainly linear: 



leaf-blades oblong to oblong-ovate. 

 Involucre campanulate, 3.5-4 mm. high; bracts mainly oblong: 

 leaf-blades lanceolate to oblong-lanceolate. 

 Leaf-blades connate-perfoliate, except in E. perj'oliatuni truncatum. 

 Leaves whorled in 3's to 6's ; blades relatively broad. 



Leaf-blades rugose, manifestly pubescent : inflorescence depressed. 

 Leaf-blades not rugose, nearly glabrous : inflorescence pyramidal. 



Leaf-blades crenate, the teeth somewhat apiculate. 36. E. trifoliatum. 



Leaf-blades sharply serrate. 37. E. purpureum. 



1. Eupatorium capillifoUum (Lam.) Small. Villous to glabrate, fennel-scented. 

 Stems 1-3 in. tall, paniculately much branched : leaves very numerous, mostly alternate ; 

 blades much compound, the segments linear-filiform to filiform, acute : heads very numer- 

 ous, in panicled racemes or panicles : involucres 2-3 mm. high, 3-6-flowered ; bracts 

 lanceolate to linear-lanceolate, glabrous, acuminate to mucronate, scarious-margined : 

 corollas white : achenes 1 mm. long, glabrous. \_E. foenkulaeeum Willd.] 



In old fields and dry soil, Virginia to Florida. Fall, 



2. Eupatorium compositif olium Walt. Puberulent to finely pubescent, more or 

 less viscid and aromatic. Stems 6-12 dm. tall, paniculately branched : leaves numerous ; 

 blades twice 3-7-parted on the lower part of the stem, gradually less compound above, and 

 entire near the top, the segments linear or nearly so : heads very numerous, in panicled 

 racemes or panicles : involucres 3-4 mm. high, 3-6-flowered ; bracts narrowly lanceolate, 

 mucronate, or the inner acuminate pubescent, scarious-margined : corollas white : achenes 

 1.5 mm. long, glabrous. \_E. coronopifolium Willd.] 



In dry soil or open woods. North Carolina to Florida and Texas. Summer and fall. 



3. Eupatoiium Eug^nei Small. Similar to E. pinnatijidum in habit, but the seg- 

 ments of the leaves commonly narrower. Heads numerous, aggregated at the ends of the 

 slender branches of the inflorescence and borne in a thyi-soid panicle : involucres 3.5 mm. 

 high ; bracts ovate to linear-spatulate, the inner mucronulate or nearly obtuse : corollas 

 white : achenes fully 1 mm. long. {E. Smithii Greene & Mohr, not Robinson.] 



In dry or sandy soil, Alabama and western Florida. Fall. 



4. Eupatorium pinnatifidum Ell. Finely pubescent. Stems 6-12 dm. tall, branch, 

 ing : leaves opposite or in whorls of 4 ; blades pinnately 2-3-parted, or the upper one- 

 twice pinnately parted or entire, the segments linear or nearly so : heads very numerouss 

 sometimes densely crowded : involucres about 3 mm. high, 6-9-flowered ; bracts ovate to 

 linear, prominently cuspidate : corollas white: achenes about 1 mm. long, glabrous. 



In dry grounds. North Carolina to Florida and Alabama. Summer and fall. 



5. Eupatorium pectinatum Small. Finely pubescent. Stems 1-2 m. tall, corym- 

 obsely branched above : leaves rather numerous ; blades mostly 5-15 cm. long, larger on 



