COMPOSITE. 159 



** Heads b — lO-Jiowered. Scales of the involucre oblong, imbricate. Leaves 

 mostly verticillate. 



5. E. pur pur eum Linn. : stem simple, hollow, or nearly solid ; leaves 3 — 6 

 in a whorl, or rarely opposite, oblong-ovate or lanceolate, more or less 

 petioled, acuminate, veiny, rough or smooth above, somewhat pubescent be- 

 neath, serrate ; heads in a large corymb, 5 — 9-flowered. E. maculatum 

 Linn. E. verticillatum Willd. E. trifoliatum Linn. E. punctatum Willd. 

 E. amcBimm Pursh. 



Low grounds. Can. and throughout the U. S. Aug. — Oct. %. — Stem 3 — 8 

 feet higli. Leaves^ 2 — 3 inches long. Flowers in a large terminal corymb, pur- 

 ple. A very variable plant. The stem is sometimes solid and purplish, and the 

 leaves three or four in a whorl, (E. verticillatum.) In other specimens the stem 

 is solid and marked with purple spots, the leaves broader, more rugose and 

 scabrous, {E maculatum.) Purple Hempweed. Joe Pye's Weed. 



*** Heads 8 — 20-Jlowered. Leaves petioled, opposite. 



G. E. aromaticum Linn. : stem terete, pubescent ; leaves opposite, pe- 

 tioled, ovate, acuminate, 3-nerved, coarsely and unequally serrate, somewhat 

 scabrous ; corymb somewhat panicled ; heads about 20-flowered-; scales of 

 the involucre 10 — 12, linear-acute, equal. E. melissoides WiUd. E. cean- 

 otliifolium Muhl. 



Low woods. Mass. to Flor. Aug., Sept. %. — Stem 2 feet high, pubescent. 

 Flowers in small corymbs, large, white, and aromatic. Distinguished from the 

 next by its pubescent stem, smaller leaves and short petioles. 



Aromatic Hempweed. 



7. E. ageratoides Linn. : stem smooth, branching at the top ; leaves op- 

 posite, on long petioles, broad-ovate, acuminate, 3-nerved, unequally and 

 coarsely serrate, thin and smoothish ; heads 12 — 20-flowered ; scales of the 

 involucre narrow-lanceolate. E. urtic^ folium Mich. 



Woods and thickets. Can. to Geor. W. to Miss. Aug.— Oct. %.—Stem 2—3 

 feet high, somewhat branched. Leaves on petioles 1 — 2 inches long, sometimes 

 slightly cordate. Heads in a compound corymb, more numerous than in the pre- 

 ceding, mostly 12 — 15-flowered. Flowers pure white, somewhat fragrant. 



Nettle-leaved Hempweed. 



**** Heads b'Jlowered. Leaves alternate or opposite, rarely lohorled. 



8. E. hyssopifolium Linn. : stem pubescent ; leaves linear-lanceolate, 

 . 3-nerved, pubescent and punctate ; lower opposite and dentate ; upper en- 

 tire, and sometimes alternate; heads 5-flowered ; scales of the involucre 10, 

 imbricate, pubescent and glandular on the back. E. linearifolium Walt. 



Sterile soil. Mass. to Flor. Aug., Sept. %.. — Stem 1 — 3 feet high. Leaves 

 small, punctate. i^/o«oers in a terminal corymb, white. Style exserte^. 



Hyssop-leaved Hempweed. 



9. E. altissimum Linn.: stem pubescent; leaves opposite, subsessile, 

 lanceolate, 3-nerved, attenuate at both ends, pubescent ; lower serrate in 

 the middle, upper entire ; heads in a terminal corymb, 5-flowered ; scales of 

 the involucre 10, oblong-linear, imbricate, somewhat obtuse, pubescent, 



Sandy woods. Penn. and Virg. W. to Miss. Aug.— Oct. %.—Stem 3—7 

 feet high. Flowers in a terminal corymb, white. Tall Hempweed. 



10. E. leucolepis Torr. tf« Gr. : stem puberulent ; leaves opposite, divari- 

 cate, lanceolate or linear, obtuse, closely sessile, serrate, very rough on both 

 Bides, punctate, strongly 1-nerved ; corymb fastigiate, canescent ; scales of 



