Along the Ohio River in southwestern Ohio in the northern extension of the Interior Low Plateau Bluegrass ecoregion (Figure 2), we found only one study that focused on the vegetation-environment relationships of riparian forests. Braun (1969) characterized the mature riparian forests associated with the rolling lowlands of wide open ravines and gentle slopes located at the Fort Hill State Memorial (Figure 2).
Along the banks of small streams, Braun (1969) described a diverse ground-flora (> 40 species), perhaps best characterized by large patches of bristly buttercup (Ranunculus hispidus Michx. var. nitidus (Chapman) T. Duncan) and a sparse overstory of American sycamore (Platanus occidentalis), American elm (Ulmus americana), boxelder (Acer negundo), and green ash (Fraxinus pennsylvanica) grading into a mixed-mesophytic forest.
Although not associated with a specific forest, Braun (1928) documented that riparian forests associated with frequently flooded flats across Highland County are characterized by an overstory of American sycamore (Platanus occidentalis), American elm (Ulmus americana), and black willow (Salix nigra Marsh.) and a diverse ground-flora including cutleaf coneflower (Rudbeckia laciniata L.), crookedstem aster (Symphyotrichum prenanthoides (Muhl. ex Willd.) Nesom), common sneezeweed -(Helenium autumnale L.), wingstem (Verbesina alternifolia (L.) Britt. ex Kearney), cup plant (Silphium perfoliatum L.), giant golden-rod (Solidago gigantea Ait.), fall phlox (Phlox paniculata L.), spotted water hemlock (Cicuta maculata L.), and field horsetail (E. arvense L.)
Finally, although Bryant (1987) describes California Woods Nature Preserve located in the Cincinnati Metropolitan area (Figure 2) as a ravine community dominated by mixed-mesophytic tree species, no specific information on the composition or structure is provided.