Eupatorium perfoliatum L.

  • Authority

    Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

  • Family


  • Scientific Name

    Eupatorium perfoliatum L.

  • Description

    Species Description - Stems 4–15 dm, conspicuously crisp-villous with long spreading hairs; lvs opposite (very rarely ternate), broad-based and strongly connate-perfoliate, tapering gradually to the acuminate tip, crenate-serrate to the base, 7–20 × 1.5–4.5 cm, sparsely pubescent or subglabrous above, more evidently hairy beneath; infl flat-topped; invol 4–6 mm, its bracts imbricate in ca 3 series, the outer less than half as long as the inner, mostly obtuse, the inner more acuminate and often pale distally; fls 9–23 per head, dull white; 2n=20. Moist or wet low grounds; N.S. and Que. to n. Fla., w. to N.D., Neb., Okla., and Tex. July–Oct. Estuarine plants from Me. and Que. avg narrower-lvd than var. perfoliatum (as described above) and have a sparser, shorter, and stiffer pubescence; these are var. colpophilum Fernald & Griscom. Forms with purple fls, form with ternate lvs, and forms with the lvs not connate have been observed.

  • Common Names