A qualitative floristic survey of Wallace Woods, Linesville, Pennsylvania, was conducted during the growing seasons of 2005–2007. The 12.9 ha tract is situated in the western portion of Crawford County, within the Northwestern Glaciated Plateau Section of the Appalachian Plateaus Province. Wallace Woods has been the property of the Pymatuning Laboratory of Ecology through the University of Pittsburgh since 1962. Seven habitats were delineated within this site: 1) Upland Hemlock–Hardwoods Forest, 2) Elevated Alluvial Woodland Terrace, 3) Golden Saxifrage Woodland Seep, 4) Skunk Cabbage Swamp, 5) Alluvial Creek Floodplain, 6) Riparian Creekbank, Gravelbars, and Mudflats, and 7) Culturally Derived Ruderal Roadside. The vascular flora consisted of 384 specific and infraspecific taxa in 229 genera from 83 families. Eighty (20.8%) taxa were exotics. Plant division representation was one Equisetophyta, three Lycopodiophyta, 15 Polypodiophyta, two Pinophyta, and 363 Magnoliophyta (97 Liliopsida, 266 Magnoliopsida). The largest five families were the Asteraceae (40), Poaceae (37), Cyperaceae (32), Rosaceae (23), and Fabaceae (12). Twenty-one taxa (5.5%) were new records for Crawford County.