CARDUACEAE 1165 
Stem pubescent: involucres 4 mm. high. 19. E. semiserratum. 
Involueres 5-6 mm. high, over 2 mm. thick. 20. E. altissimum. 
Lower leaf-blades decidedly broadest above the middle. 
Involueres about 5 mm. high: cauline leaves with entire 
blades. 21. E. tortifolium. 
Involucres about mm. high: cauline leaves with toothed 
blades. 22. E. cuneifolium. 
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. 23. E. leucolepis. 
Inner bracts of the involucre awn-tipped: leaf-blades 3- 
i 24. E. Mohrii. 
ri d 
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. 25. E. album. 
Outer bracts of the involucre linear, acute: inner bracts 
spatulate, petaloid, mucronate. 26. E. petaloideum. 
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. rotundifolium. 
Leaf-blades manifestly longer than broad, rounded or 
broadly cuneate at the base. 
Involucres over 4 mm. high: leaf-blades rounded at the 
ase. 29. E. pubescens. 
Involucres less than 4 mm. high: leaf-blades broadly cu- 
neate at the base. 30. E. scabridum 
Leaf-blades sharply serrate. 31. E. sessilifolium. 
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. 32. E. Chapmanii. 
Involuere campanulate, 3.5-4 mm. high; bracts mainly oblong: 
leaf-blades lanceolate to oblong-lanceolate. 33. E. cuneatum. 
Leaf-blades connate-perfoliate, except in E. perfoliatum truncatum. 34. E. perfoliatum. 
Leaves whorled in 3's to 6’s; blades relatively broad. 
Leaf-blades rugose, manifestly pubescent : inflorescence depressed. 35. E. maculatum. 
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 capillifólium (Lam.) Small. Villous to glabrate, fennel-scented. 
Stems 1-3 m. 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. [ÆE. foenieulaceum Willd. } 
In old fields and dry soil, Virginia to Florida. Fall, 
2. Eupatorium compositifdlium 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. Eupatorium Eugénei Small. Similar to E. pinnatifidum 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 thyrsoid panicle : involucres 3.5 mm. 
high; bracts ovate to linear-spatulate, the inner mucronulate or nearly obtuse: corollas 
white: achenes fully 1 mm. long. [ÆE. 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. Bupatorium pectinàtum Small. Finely pubescent. Stems 1-2 m. tall, corym- 
obsely branched above: leaves rather numerous ; blades mostly 5-15 em. long, larger on 
