GENUS 4. THISTLE FAMILY. 359 
10. Eupatorium semiserratum DC. 
Small-flowered Thoroughwort. 
Fig. 4161. 
E. semiserratum DC. Prodr. 5: 177. 1836. 
Pubescent or puberulent, loosely branched 
above, 2°-3° high. Leaves rather thin, short- 
petioled, oblong-lanceolate to spatulate, acute 
or obtusish at the apex, narrowed at the base. 
sharply serrate, at least above the middle, 
2’-4’ long, 5’-12” wide, 3-nerved, usually 
with short branches in their axils; inflores- 
cence cymose-paniculate; heads 2-3” high, 
about 5-flowered; involucre campanulate, 
its bracts linear-oblong, obtuse, canescent, 
imbricated in 2 or 3 series, the outer shorter, 
flowers white. 
In dry soil, Virginia to Florida, Missouri, 
Arkansas and Texas. Aug.—Sept. 
Ir. Eupatorium altissimum L. Tall 
Thoroughwort. Fig. 4162. 
Eupatorium altissimum L. Sp. Pl. 837. 1753. 
Densely and finely pubescent, corymbosely 
much-branched above, 4°-8° high. Leaves 
lanceolate, acuminate at the apex, tapering 
below into a short petiole, roughish, rather 
thick, sparingly dentate above the middle. 
or some of them entire, strongly 3-ribbed, 
2’-3' long, 3-12” wide; inflorescence dense- 
ly cymose-paniculate; heads about 5-flow- 
ered, 3’-4” high; involucre campanulate, 
its bracts oblong, obtuse or truncate, densely 
pubescent, imbricated in about 3 series, the 
outer shorter; flowers white. 
In dry open places, Pennsylvania to North 
Carolina, Alabama, Illinois, Minnesota, Ne- 
braska and Texas. Sept.—Oct. 
12. Eupatorium sessilifélium L. Up- 
land or Bastard Boneset. Fig. 4163. 
Exupatorium sessilifolium L. Sp. Pl. 837. 1753. 
Glabrous throughout, or pubescent above, 
branched near the summit, 2°-6° high. Leaves 
opposite, or the lower rarely in 3’s, closely ses- 
sile, lanceolate or ovate-lanceolate, long-acumi- 
nate, thin, sharply serrate, 3-6’ long, 4-12’ 
wide, inflorescence cymose-paniculate; heads 
4°-5” high, about 5-flowered; involucre cam- 
panulate, its bracts linear-oblong, imbricated in 
about 3 series, the inner obtuse, the outer acut- 
ish, shorter; flowers white. 
In dry woods, Vermont to Massachusetts, Penn- 
sylvania, Georgia, Alabama and Missouri. Aug.— 
Oct. A related plant, described under the name 
Eupatorium sessilifolium Brittonianum Porter, 
has leaves ovate or oblong-ovate, sparingly and 
finely serrate, firm, rounded at the base, acute, the 
upper 1-2’ long, 6”-9” wide, pinnately veined, B 2 5 
dark green; cymes dense, their branches puberulent. It is known only from Budd’s Lake, N. J. 
