Ptilimnium costatum (Elliott) Raf.

• Authority

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

• Family

  Apiaceae

• Scientific Name

  Ptilimnium costatum Raf.

• Description

  Species Description - Robust, to 1.5 m, branched above; lvs 5–15 cm, pinnately dissected into innumerable filiform segments 5–10 mm, the primary divisions verticillate along the rachis; petiole well developed, the stipular wings none or barely developed at the base only; umbels long-pedunculate, 4–8 cm wide; bracts usually filiform and undivided; rays 12–30, 2–4 cm, fr broadly ovoid, 3–3.5 mm; styles 1.5–3 mm, spreading; 2n=22, 32. Swamps and wet woods; irregularly from s. Ill. and Mo. to N.C., Ga., and Tex. July–Sept.

• Common Names

  big mock bishop's-weed