Though Lily Pond has the most developed shoreline of all the Long Pond Greenbelt’s ponds and lacks public access, it is home to the Williamson Preserve, so named to honor the family who sold the property to The Nature Conservancy. Sitting at the pond’s southeastern edge, the 1.4-acre preserve provides a natural corridor connecting Lily Pond to Little Long Pond.

Classified by ecologists as a coastal plain pond, Lily Pond represents an area of exposed water table fed solely by groundwater via precipitation with no inlet or outlet. Its water level fluctuates both seasonally and annually and can provide a good indicator of the level of our groundwater table. Being a shallow pond, periods of low precipitation can expose a broad expanse of gently sloping beach along the pond’s edges. Seeds in the beach sand that have been underwater and dormant for several years can become stimulated to germinate when exposed. Among the specialized plants that may colonize the newly revealed shoreline are many rare plants like rushes, sedges, bladderworts, certain wildflowers, and the insectivorous sundews.