1. Leaves deeply pinnatifid or bipinnatifid; plants annual; pappus of 2 scales.

P. hysterophorus

1. Leaves merely toothed or crenate; plants perennial; pappus of 2–3 weak awns.

P. integrifolium

All species found in Parthenium

Parthenium hysterophorusSANTA MARIA 
Parthenium integrifoliumAMERICAN FEVERFEW, WILD QUININE 


MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. March 21, 2018.