Helianthus annuus 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

    Helianthus annuus L.

  • Description

    Species Description - Coarse, rough-hairy annual (0.5–)1–3 m; lvs chiefly alternate (except the lowermost), mostly toothed, long-petiolate, ovate or broader, at least the lower cordate in well developed plants; heads large, the red-purple (yellow) disk seldom under 3 cm wide; invol bracts ovate or ovate-oblong and abruptly narrowed above the middle to the acuminate tip, ciliate and with some rather long coarse hairs on the back; receptacle flat or nearly so, its bracts inconspicuously hairy at the tip; 2n=34. A weed in disturbed sites, especially in moist, low ground, throughout the U.S. and adj. Can. and Mex. July–Sept. Typical wild plants are branched, with several or many heads. Cult. forms, which readily escape, have solitary (or few), often much larger heads. (H. lenticularis; H. aridus)

  • Common Names

    common sunflower