Eupatorium hyssopifolium L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Stems solitary (seldom several) from a short crown, strigose or scabrous-puberulent, especially above; lvs verticillate in 3’s or 4’s, or sometimes merely opposite, or even alternate above, narrow, mostly 6–40 times as long as wide, sessile or tapering to a slender base, spreading or ascending, glandular-punctate, otherwise glabrous or slightly hairy chiefly on the main veins beneath, the principal ones subtending conspicuous axillary fascicles of reduced lvs; invol 4–7 mm, its bracts imbricate, broadly rounded to acute, the inner narrowly scarious-margined; fls 5, the cor white, 3.5–4 mm; 2n=20, 30, 40. Fields and other open places, especially in dry, sandy soil; coastal states from Mass. to n. Fla. and w. to La., and sometimes inland to O., Ky., and Tenn. Aug.–Oct.