This study determines the current and historic distributions of Prenanthes crepidinea Michaux (Asteraceae: Lactuceae) and describes its habitat and life history. A phytogeographical study based on herbarium material was conducted to delimit historic and current distributions of P. crepidinea. Ecological data were gathered from herbarium specimens. A literature search was conducted for information about P. crepidinea to enhance the herbarium study.

An in-depth field study over two seasons, 1998 and 1999, was made at three extant sites, providing a characteristic life history and habitat description for the species. Associated plant species, pollinators, and parasites were investigated, with voucher specimens for all associated plant species deposited in the herbaria of Youngstown State University (YUO) and Carnegie Museum of Natural History (CM).