Vegetation-substrate relationships of a sandstone outcrop located along the Ohio River are presented. Dominant species were crustose lichens (Endocarpon pusillum Hedw., Psorotichia schaereri (Massal.) Arnold, and Rinodina oxydata (Massal.) Massal.), Panicum virgatum L., and Amorpha fruticosa L. Five dominance types were identified from cluster analysis based upon composition of cryptogams and vascular plants: 1) Atrichum angustatum (Brid.) B.S.G.-Hypericum prolificum L., 2) Amorpha fruticosa-Panicum virgatum, 3) Ulmus rubra Muhl., 4) Endocarpon pusillum-Psorotichia schaereri, and 5) Rinodina oxydata. Discriminant-function analysis identified five important substrates in the dominance type structure on the outcrop: 1) dripway rock, 2) talus rock, 3) bare rock, 4) rock depression, and 5) loess soil. Disturbance from river flooding, degree of shading, and aspect are thought to maintain the vegetation.