The Biological Station is the last remaining vestige of the great wooded and cattail marsh which once covered the area from the lighthouse pier as far south as Falls Street and with arms of the marsh reaching up as far as Court Street."
- Peter Paul Kellogg, 1964
The floodplain forest and marsh are located on a delta built of sediments deposited by the Cayuga Inlet and Fall Creek at the mouth of Cayuga Lake. In the hardwood forest, sycamore (Platanus occidentalis), cottonwood (Populus deltoides), silver maple (Acer saccharinum), box elder (A.negundo), red ash (Fraxinus pensylvanica), and swamp red maple (a red maple ¥ silver maple hybrid, A.¥freemanii) are dominant. American elm (Ulmus americana) was once a dominant species in swamps and floodplains like this one, and a few scattered trees remain.
Trees are festooned with vines, including Virginia creeper (Parthenocissus quinquefolia), poison ivy, and grape (Vitis riparia). Red-osier dogwood (Cornus sericea) and cranberry viburnum (Viburnum trilobum) abound in the understory. Characteristic herbs are sensitive fern (Onoclea sensibilis), white snakeroot (Eupatorium rugosum), and spotted jewelweed (Impatiens capensis).
This site used to include one of the last vestiges of a large cattail marsh that once dominated the mouth of the lake. What little cattail marsh remains is near Fall Creek near the golf course and at Hog Hole, a wetland at the southwest corner of the lake. Reed canary grass (Phalaris arundinacea), wild black currant (Ribes americanum), and arrow arum (Peltandra virginica) are found there.