Heracleum sphondylium L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Lvs pinnate with mostly 5(–9) toothed (and often also cleft) segments; bracts few or none; otherwise much like no. 1 [Heracleum lanatum Michx.], but the lf-segments often smaller and the umbel sometimes with as many as 45 rays; 2n=22. Native of Eurasia, casually intr. in waste places from Nf. to N.Y.