Ambrosia

• Authority

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

• Family

  Asteraceae

• Scientific Name

  Ambrosia

• Description

  Genus Description - Heads numerous, small, unisexual, rayless; staminate heads in a racemiform or spiciform, bractless infl, with subherbaceous, 5–12-lobed invol, flat receptacle with slender, filiform-setose pales, monadelphous filaments, scarcely united anthers, and undivided style; pistillate heads borne below the staminate, in the axils of lvs or bracts, with closed, nutlike or burlike invol bearing 1–several rows of tubercles or spines and containing 1(–several) pistillate fls without cor; pappus none; herbs (ours) or shrubs; lvs often lobed or dissected, in most spp. opposite at least below. 40, predominantly New World. (Franseria)

• Common Names

  ragweed