United States, Illinois, Cook, Pioneer Woods Forest Preserve, Willow Springs: 107th Street, 0.5 mile west of La Grange Road. Near top of south-facing slope leading to creek. South of parking cul-de-sac.
Degraded slope of oak woodland. Associates: Carya ovata, Quercus alba, Quercus rubra, Amphicarpaea bracteata, Polygonum virginianum, Circaea lutetiana var. canadensis, Cinna arundinacea, Leersia virginica, Bromus pubescens. Vine with inconspicuous white flowers in leaf axils. Uncommon.