United States, Illinois, Cook, Penn Central RR Prairie.
Penn Central RR Prairie, Matteson. Old Plank Rd. Trail, R-11, between I-57 and Cicero Ave. T35N, R13E Sec 21 south edge of SW4SE4. Collected 400' east of I-57 overpass, atop bank on north side of former railroad bed.
Dry, mesic prairie strip at top of railroad embankment